De Anima (On the Soul) #

A comprehensive study of Aristotle’s De Anima and the nature of the soul. These lectures examine the soul as substantial form and first act of a living body, analyzing its powers—nutritive, sensitive, and intellectual—and demonstrating the immateriality of the human intellect through its grasp of universal truth.

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Lectures #

1. The Structure and Order of Aristotle’s Natural Philosophy #

This lecture establishes the foundational structure of Aristotelian natural philosophy, explaining how Aristotle proceeds from the general study of motion and change to particular kinds of change (local motion, qualitative change, and growth). Berquist traces the correspondence between Aristotle’s threefold division of change and modern scientific disciplines (physics, chemistry, biology), and then explains the organization of Aristotle’s books on living things through the principle of abstraction and concretion—moving from consideration of the soul in relative abstraction through intermediate books that apply the soul’s powers to bodily organs, down to particular species. The lecture emphasizes that sciences are distinguished by their diverse ways of separation from matter, a principle that will later lead to the distinction between natural philosophy, mathematics, and metaphysics.

2. The Premium Structure and Excellence of Knowledge of the Soul #

This lecture examines the proem (premium) to Aristotle’s De Anima, explaining the two-part structure of Aristotelian treatises and establishing why knowledge of the soul is supremely desirable. Berquist discusses two criteria for evaluating the excellence of knowledge: the object known and the certitude of knowing. He contrasts knowledge with love, explores how we come to know the soul through its operations, and situates the study of the soul within the broader framework of natural philosophy and its preparation for metaphysics.

3. The Soul as Principle of Life: Definition and Desirability #

This lecture establishes why knowledge of the soul is supremely desirable and how to define it. Berquist argues that the soul, understood as the first cause of life in living bodies, excels in two respects: it is the best thing in the material world, and we have immediate inward certainty of its existence. The lecture clarifies what the ancient Greeks meant by ‘soul’ (ψυχή/anima) and why modern dismissal of the term represents a philosophical catastrophe, then addresses the fundamental difficulties in investigating the soul’s nature.

4. Difficulties in Investigating the Soul’s Nature #

This lecture explores the major methodological and conceptual difficulties Aristotle identifies when investigating what the soul is. Berquist examines five key problems: the method of investigation itself, determining the genus of the soul, whether there is one definition or multiple definitions of soul, the relationship between the soul’s parts and its operations, and whether knowing the soul’s substance helps us understand its properties or vice versa. The lecture also compares Plato’s two inadequate theories of the soul (as a distinct substance versus as harmony/order) and previews Aristotle’s synthetic resolution.

5. Definition, Nature, and Substance in Natural Philosophy #

This lecture examines the concept of definition itself, exploring how the terms ’nature’ (φύσις), ‘substance’ (οὐσία), and ‘what it is’ (τί ἐστι) are used interchangeably to express the essence of things. Berquist traces the historical understanding of definition from Ammonius Hermaeus through Thomas Aquinas, and demonstrates how different sciences (mathematics, natural philosophy, and wisdom) require different methods of defining. The lecture also addresses the particular difficulty of defining the soul, given its hidden nature and immaterial operations.

6. Definition, Substance, and the Problem of Defining the Soul #

This lecture examines how definitions function differently depending on the kind of thing being defined. Berquist explores the fundamental distinction between defining substances (which exist by themselves) and accidents (which exist in another), then applies this framework to the central question: whether the soul should be defined as a complete substance, an accident, or as a form that is part of substance. The lecture also traces the etymological connection between error (and the Greek plane) and wandering, illustrating how disordered reasoning leads to confusion.

7. Christ on Error, Ignorance, and the Road of Knowledge #

This lecture examines the nature of error through Christ’s teaching to the Sadducees about resurrection, establishing ignorance as the fundamental cause of error. Berquist traces the connection between error (planē—wandering) and ignorance, distinguishing between remote causes (pride and curiosity) and proximate causes (ignorance), while exploring how knowledge requires following a proper methodological road. The discussion introduces the four kinds of accidental causality and examines ignorance specifically as a causa removens prohibens—a cause that removes what would prevent error.

8. The Soul’s Activities, Passions, and Separability from Body #

Berquist explores the methodological and metaphysical difficulties surrounding the soul’s passions (emotions) and activities, particularly whether the soul can exist independently of the body. The lecture addresses how errors arise through imagination and likeness, examines the connection between a thing’s being and its operations, and demonstrates why investigating what the soul does is essential to understanding what it is—with direct implications for the question of the soul’s immortality.

9. Emotions, the Passions of the Soul, and Their Bodily Nature #

Berquist explores Aristotle’s teaching on the passions of the soul—emotions like anger, fear, desire, and joy—demonstrating that they are inseparable from bodily changes and operations. He distinguishes between the formal (logos) and material (bodily) aspects of emotions, explains how emotion names are carried over to acts of the will while dropping the bodily component, and shows why some emotion names cannot be properly applied to God. He also develops a detailed taxonomy of eleven emotions divided into concupiscible and irascible categories, and reflects on how human pleasure and education involve an ordering from sensible to intellectual goods.

10. The Soul as Form of the Body: Three Divisions #

Berquist guides students through Aristotle’s method of investigating the definition of the soul by division rather than enumeration. The lecture covers three divisions on the side of the soul (substance vs. accident, form vs. matter, first act vs. second act) and three divisions on the side of the body (natural vs. artificial, living vs. non-living, organized vs. disorganized). The discussion establishes the soul as substantial form—the actualizing principle of a living, organized body—while addressing why the soul cannot be understood as either a complete independent substance or merely the body’s organization.

11. The Three Divisions: Defining the Soul Through Being and Act #

Berquist explores Aristotle’s method of defining the soul through systematic division rather than simple enumeration. The lecture covers three divisions concerning the soul itself: (1) the soul as substance rather than accident; (2) the soul as form rather than matter within substance; and (3) the soul as first act rather than second act. Through these divisions, Berquist establishes that the soul is the first act of a natural body that possesses life, while addressing why equivocation in ’thing’ and ‘being’ is not a logical problem but reflects the analogical structure of reality.

12. The Soul as Substantial Form: Three Divisions #

This lecture explores Aristotle’s three-fold method for investigating the nature of the soul through systematic division. Berquist clarifies that the soul is a substantial form (not an accident), exists as first act (not merely operation), and actualizes a natural, organized body. The lecture addresses the apparent contradictions in substantial change and demonstrates how the soul differs from Platonic and Cartesian conceptions through the matter-form hylomorphic framework.

13. The Soul as First Act and the Definition of the Soul #

This lecture completes the definition of the soul as “the first act of a natural body composed of tools” by examining Aristotle’s distinctions between first and second act, clarifying what it means for the body to be composed of tools (organon), and resolving the classical problem of how the soul and body can be one substance. Berquist emphasizes the importance of understanding the soul’s relationship to the body through the form-matter relationship rather than as two separate complete substances, and addresses the linguistic precision required to avoid equivocation about the word ‘body.’

14. The Soul as Form and First Act of the Body #

This lecture explores Aristotle’s definition of the soul through critical analysis of competing philosophical positions and their strengths and weaknesses. Berquist demonstrates how the Thomistic synthesis resolves the classical problem of body-soul unity by understanding the soul as the substantial form and first act of a natural, organic body. The lecture employs proportional likenesses—particularly the examples of the axe and the eye—to clarify how the soul differs from both accidental forms and complete spiritual substances, and concludes with an application of soul-body relations to political philosophy.

15. The Soul as Form: Proportions and First Act #

Berquist explains Aristotle’s definition of the soul through two key proportions: the soul is to the body as the ability to chop is to an axe, and as the ability to see is to the eye. The lecture emphasizes that the soul is a first act (entelekeia), not a second act (operation), and explores how proportional reasoning is essential for discovery in philosophy and science. The discussion clarifies the relationship between definition and demonstration, and addresses why certain bodies are animated while others are not.

16. Wonder, Definition, and the Soul as First Act #

This lecture explores the philosophical foundations of inquiry by examining wonder as the beginning of philosophy, drawing from Plato and Aristotle. Berquist then transitions to analyzing how definitions relate to demonstrations in logic, using examples like knives and marriage to show how definition can be premise, conclusion, or complete demonstration in different form. The lecture culminates in examining Aristotle’s definition of the soul as the first act of a natural body composed of organs, contrasting it with the second act (operations), and establishing the hierarchy of living powers from nutrition through intellection.

17. The Soul as Form: Definition and the Five Powers #

This lecture explores Aristotle’s definition of the soul as the first act (form) of a living body, demonstrated through proportional reasoning and the distinction between form and matter. Berquist examines the five genera of powers of the soul (nutritive, sensitive, appetitive, locomotive, and thinking) and their hierarchical relationships, emphasizing how the soul is that by which we first live, sense, and understand—not as matter or subject, but as form and intelligible principle.

18. The Five Powers of the Soul and Four Grades of Life #

This lecture examines Aristotle’s doctrine of the five genera of powers of the soul (nutritive, sensitive, appetitive, locomotive, and intellectual) and explains how they organize into four grades of life. Berquist analyzes the hierarchical ordering of these powers, their material and immaterial aspects, and demonstrates why the appetitive power does not constitute a separate grade of life since it necessarily accompanies both sensation and understanding. The lecture also addresses Church teaching on the rational soul as the form of the body, citing conciliar documents from Vienna (1311-1312) and the Fifth Lateran Council (1513).

19. The Five Powers, Four Grades, and Three Souls #

This lecture explores why the soul is traditionally divided into three types (plant, animal, rational) despite having five distinct powers of life. Berquist examines the hierarchical ordering of nutritive, sensitive, locomotive, appetitive, and thinking powers, explaining why the appetitive power does not constitute a separate grade of life. The discussion emphasizes how the soul is understood primarily through its degree of immateriality and rising above mere matter, with extended treatment of the appetitive powers and their divisions into sense desire and rational desire (will).

20. Pleasures, Desire, and the Hierarchy of Souls #

This lecture explores the nature of pleasure and desire (epithumia and thumos) as appetitive powers that necessarily accompany sensation and reason. Berquist examines how different kinds of pleasures correspond to different levels of being—animal pleasures shared with beasts, human pleasures involving the union of body and soul, and angelic/divine pleasures of understanding—and uses this hierarchy to address Mill’s objection that utilitarianism reduces human philosophy to bestiality. The discussion culminates in clarifying how the soul is known through its powers and acts in a specific epistemic order.

21. The Nutritive Soul and Generation in Living Things #

This lecture examines Aristotle’s account of the nutritive soul (the first and most common power of all living things) and its operations: feeding, growth, and generation. Berquist explores how the soul functions as a cause in three ways (form, mover, end), why generation is the most natural operation of living things, and refutes materialist errors (particularly Empedocles) that attempt to reduce life to blind physical forces. The lecture demonstrates that the desire to perpetuate oneself through generation is a natural striving to be like God, grounded in both Platonic and Aristotelian philosophy.

22. The Nutritive Soul: Food, Growth, and Generation #

This lecture examines Aristotle’s account of the nutritive soul (ψυχή θρεπτική) through a detailed analysis of food as the object of the feeding power, the distinction between what is fed, that which feeds, and the means of feeding. Berquist refutes materialist accounts of life (particularly Empedocles and the fire theory) by demonstrating how the soul, as a unifying principle, accounts for the determinate order and limit in living growth. The lecture culminates in understanding why the nutritive soul is properly defined by its ultimate act—generation or reproduction—and how this understanding illuminates the sacraments of Christian initiation.

23. Temperance, Purity, and Catharsis: Four Types of Purification #

This lecture explores the integral parts of temperance—particularly verecundia (shame) and anastasia (spiritual beauty)—and explains why these virtues are associated with purity. Berquist develops a comprehensive analysis of catharsis across four domains: bodily, emotional, rational, and volitional. He connects this to Aristotle’s three rules for acquiring moral virtue and demonstrates how pleasure corrupts judgment most easily, making temperance essential for both moral and intellectual life.

24. Sensation as Undergoing: Potency and Act in Sensing #

This lecture explores Aristotle’s fundamental claim that sensation is an undergoing—a being acted upon by sensible objects rather than an active process. Berquist clarifies the linguistic and philosophical challenges in translating Greek terms like pascein (suffering) and dynamis (power/potency), arguing that English obscures the distinction between active and passive senses of these words. The lecture refutes Empedocles’ theory that ’like knows like’ through material composition, establishing instead that the senses must be in potency (ability) initially, requiring external objects to actualize them. The analysis illuminates how sensation involves actualization of potential rather than mere alteration.

25. Two Potencies and Two Acts in Sensation and Understanding #

Berquist explores Aristotle’s distinction between two kinds of potency (ability) and two kinds of act in both understanding and sensation. By first analyzing how reason operates in two distinct ways—the ability to acquire knowledge and the ability to exercise it—he then shows how sensation operates analogously. The lecture clarifies why sensation requires external objects while understanding can be exercised at will, and explains how learning differs from simple alteration.

26. The Three Meanings of Sensible and Proper vs. Accidental Sensation #

This lecture explores Aristotle’s distinction between three kinds of sensibles: proper sensibles (perceived by only one sense with certainty), common sensibles (perceived by multiple senses), and accidental sensibles (recognized through something other than sensation itself). Berquist clarifies how we speak of sensing (e.g., ‘hearing a cat’) in ways that obscure the actual nature of sensation, and explains why the senses are more easily deceived about accidental and common sensibles than about proper sensibles. The lecture distinguishes between what is sensed ‘as such’ (per se) versus ‘by happening’ (per accidens), with extended discussion of examples like hearing a meow versus hearing a cat, and tasting salt versus sugar.

27. Happiness, Fortune, and the Etymologies of Human Flourishing #

This lecture explores the concept of human happiness (eudaimonia) through the etymological analysis of three key terms: eudaimonia (Greek), felicitas (Latin), and happiness (English). Berquist examines how each word’s etymology—pointing to divine daemon, fruitfulness, and luck respectively—reveals different dimensions of human flourishing. The lecture emphasizes that while virtue and choice are essential to happiness, fortune and higher beings also play a role, as demonstrated through Shakespearean examples and the distinction between happiness as the ultimate end versus happiness as joy or contentment.

28. Light, Transparency, and the Rejection of Corpuscular Theory #

Berquist analyzes Aristotle’s account of light and the transparent medium in De Anima Book II, focusing on Aristotle’s rejection of Empedocles’ theory that light is subtle bodies spreading through space. The lecture examines the logical structure of Aristotle’s arguments, compares ancient philosophy with modern physics (photons, wave-particle duality), and discusses the necessity of a transparent medium for vision. Berquist also reflects on the proper roles of common versus private experience in philosophy and science.

29. Sight, Hearing, and the Continuous in Knowledge #

This lecture examines Aristotle’s argument for the superiority of sight among the senses and explores how hearing serves a unique function in learning through speech. Berquist develops the philosophical principle that the continuous is foundational to all human knowledge and language, tracing how equivocal terms used in philosophy and theology derive their primary meanings from the continuous. The lecture connects sensory perception to reason’s immateriality and illustrates these principles through examples from four-element theory, memorization, and the pedagogy of Christ and Socrates.

30. Sensory Reception and the Immateriality of Knowing #

Berquist explores Aristotle’s account of how the senses receive sensible forms without matter, distinguishing this from material alteration. The lecture examines three types of reception—material, sensory, and rational—and demonstrates how sense organs possess a delicate harmony or proportion that can be damaged by excessive stimuli, unlike reason which becomes enhanced by more profound objects. This distinction reveals the immaterial nature of intellect and prefigures the discussion of inward senses and reason in Book III.

31. The Soul-Spirit Distinction and Interior Sensing #

This lecture explores the fundamental distinction between soul (anima) and spirit (pneuma) through both theological and philosophical lenses, focusing on St. Paul’s epistle to the Corinthians and Thomas Aquinas’s commentary. Berquist examines how the human person can be characterized as either ‘animalis’ (concentrated on bodily powers) or ‘spiritualis’ (elevated by God’s Spirit), and begins Aristotle’s investigation of interior sensing powers that must unify and reflect upon the five exterior senses.

32. Sensing Our Sensing and Cross-Sensory Discrimination #

This lecture investigates two key problems in Aristotle’s theory of sensation: (1) whether we sense our own acts of sensing (e.g., sensing that we see), and (2) how we discriminate between objects of different senses (e.g., white and sweet). Berquist examines Aristotle’s arguments for the necessity of an internal or common sense (κοινὴ αἴσθησις) that unifies sensory information and shows how sensation involves receiving sensible form without matter.

33. The Common Sense and Discrimination Between Sensibles #

This lecture examines Aristotle’s argument for an inward sense power called the common sense (or central sense) based on the fact that we can discriminate between objects of different external senses—such as distinguishing white from sweet. Berquist explores why no single external sense or combination of external senses can make this discrimination, and how this requires a unified inner power that receives impressions from all senses simultaneously. The lecture addresses the metaphysical problem of how one power can receive multiple sensibles, drawing analogies to syllogistic reasoning and geometric points.

34. The Common Sense and the Reception of Contraries #

This lecture examines how a single internal sense power (the common sense) can simultaneously receive and discriminate between different sensibles from multiple external senses without being overwhelmed by contrary sensations. Berquist contrasts how reason can know opposites together (unlike matter, which cannot be acted upon by contraries simultaneously) and uses geometric analogies—particularly the point as the beginning of multiple lines—to explain how the common sense is one in number yet multiple in definition.

35. Transition from Sense to Reason in Aristotle’s De Anima #

This lecture marks the transition from studying the senses to examining reason, following Aristotle’s De Anima Book III, Chapter 3. Berquist explains how pre-Socratic philosophers failed to distinguish sensing from thinking because they were materialists who did not recognize immaterial cognition. The lecture explores how ancient errors resurface in modern philosophy and establishes key definitions of knowing, including the distinction between grasping and judging.

36. Brain, Thought, and the Error-Prone Mind #

This lecture examines why the brain is not the organ of thought, despite the apparent connection between brain damage and impaired thinking. Berquist uses logical analogies to distinguish between an object of thought and an organ of thought, arguing that reason’s immateriality can only be established once we recognize that the brain provides images (the object) rather than serving as the instrument of thought. The lecture also emphasizes Aristotle and Thomas’s analysis of human error—that mistake is more natural to humans than truth, requiring long study and external teaching to arrive at knowledge.

37. Imagination, Sense, and Opinion: Distinction and Definition #

This lecture examines the nature of imagination (phantasia) and how it differs fundamentally from sensation, opinion, and understanding. Berquist walks through Aristotle’s logical elimination of false identifications, establishing that imagination is neither a power of sensation nor a habit of opinion, but rather a motion produced by sensation that persists even when sensory objects are absent. The discussion includes the Pythagorean numerology connecting the four epistemic powers to the numbers one through four, and explores concrete examples from dreams, sleep, and animal behavior to illustrate these distinctions.

38. Imagination as Motion: Distinguished from Sensation and Opinion #

This lecture completes Aristotle’s analysis of imagination (phantasia) by establishing what imagination is NOT (sensation, opinion, science, or their combinations) and then positively defining it as a motion produced by the act of sensation. Berquist explores how imagination differs fundamentally from sensation in its ability to occur without present objects and its liability to falsity, uses detailed examples of optical illusions and sensory deception to illustrate the distinction between proper, common, and accidental sensibles, and explains imagination’s ontological status as a ‘moved mover’ that generates weaker but persistent images within the soul.

39. Composition, Parts, and God’s Simplicity #

This lecture explores the equivocal meaning of ‘composition’ (compositio) and ‘parts’ across different types of wholes—continuous quantities, discrete quantities, matter-form composites, and definitions. Berquist demonstrates how understanding these distinctions is essential for defending God’s absolute simplicity and clarifying Trinitarian theology against misinterpretation. The discussion traces how Aristotle and Thomas Aquinas systematically distinguish types of composition to avoid sophistic arguments.

40. Composition, Parts, and Divine Simplicity #

This lecture explores the equivocal nature of the terms ‘composition’ and ‘parts’ across different domains—quantitative wholes, matter-form composites, definitions, and universal wholes—with particular attention to how understanding these distinctions clarifies God’s absolute simplicity and resolves apparent contradictions in Trinitarian theology. Berquist emphasizes that Aristotle’s analysis of these terms in Metaphysics V is essential for avoiding sophistic arguments and for properly understanding both natural philosophy and theology.

41. History as Incomplete Knowledge and the Undergoing Understanding #

This lecture explores why historical knowledge is necessarily incomplete, drawing on Thomas Aquinas’s analysis of the word ‘history’ as investigation. Berquist then transitions to the intellectual powers of the soul, specifically distinguishing between grasping (apprehensio) and judging (iudicium) as two distinct operations of knowing, and introduces the concept of the undergoing or receptive understanding (intellectus possibilis) that will be the focus of subsequent chapters.

42. Understanding and Sensation: The Immateriality of Mind #

This lecture explores Aristotle’s argument for the immateriality of the intellect by comparing understanding to sensation. Berquist demonstrates how the intellect, like the senses, receives its objects while remaining unmixed with matter, and how this immaterial reception allows the mind to know all material things universally rather than as singular particulars.

43. Universals, Reason, and the Immateriality of Mind #

Berquist explores Aristotle’s doctrine that reason is the place where universals exist immaterially, contrasting this with Platonic Forms. He develops arguments for the immateriality of the intellect based on its capacity to receive all material natures, and examines how reason understands the continuous (mathematical objects) in a non-continuous way through definition. The lecture also clarifies the distinction between sensation (which receives singulars) and understanding (which receives universals), establishing foundational principles for how human knowledge operates.

44. Understanding as Immaterial Reception: Reason’s Object and Potency #

Berquist clarifies Aristotle’s doctrine that understanding, like sensation, is a form of undergoing or being acted upon by its object, but in a wholly immaterial way. The lecture establishes that reason must be immaterial because it receives all material natures universally, and explores the distinction between a particular thing and its essence (what-it-is). The key innovation is explaining why understanding enhances rather than impedes further understanding—unlike sensation, which can be damaged by overly strong stimuli.

45. The Object of Reason: Essence and Universals #

This lecture explores Aristotle’s teaching on the proper object of the intellect or reason, which is the ‘what it is’ (essence) of things. Berquist examines the distinction between particular things and their universal essences, explaining why this distinction exists in material things but not in immaterial beings like angels or God. The lecture demonstrates how understanding reason’s object as universal proves the intellect cannot be a body, and applies these principles to theological problems about divine simplicity.

46. Divine Simplicity and Analogical Language About God #

This lecture explores how human reason, naturally oriented toward understanding material things composed of matter and form, must speak about God who is entirely simple and immaterial. Berquist examines the problem of using concrete and abstract language about God (e.g., ‘God is wise’ vs. ‘God is wisdom itself’), showing why both affirmation and denial of such predicates are necessary. He develops this through analysis of the distinction between what-a-thing-is and the thing itself in material vs. immaterial beings, drawing on Aristotle, Thomas Aquinas, and Pseudo-Dionysius.

47. Undergoing, Immateriality, and the Object of Understanding #

This lecture addresses two fundamental objections to how an immaterial intellect can be acted upon by material things, and resolves the paradox of why material things become intelligible but do not themselves understand. Berquist emphasizes the critical importance of understanding how the Greek and Latin word for ‘suffering’ (passio/πάσχειν) has multiple meanings—from destructive passion to perfecting reception—and traces how this linguistic complexity affects our understanding of intellection. The lecture culminates in explaining why immateriality is essential to understandability and how things separated from matter become actually intelligible.

48. The Active and Passive Intellect: Powers and Actualization #

This lecture explores Aristotle’s doctrine of the two powers of the intellect: the passive or undergoing intellect (intellectus possibilis) that receives intelligible forms, and the active or agent intellect (intellectus agens) that actualizes potentially intelligible things by separating universal natures from singular material conditions. Berquist develops the analogy between matter-and-art in the physical order and the passive-active intellect in the intelligible order, using the comparison of light to illuminate how immaterial power acts upon images derived from sensation and imagination.

49. The Acting Upon Understanding and Immateriality #

This lecture examines Aristotle’s doctrine of the acting upon understanding (active intellect) as presented in De Anima III.5. Berquist explores why both an undergoing understanding and an acting upon understanding are necessary for human knowledge, how the acting upon understanding actualizes potentially understandable things by separating universals from material singulars, and why both powers must be immaterial. The lecture also discusses the natural light of reason, the relationship between intellect and imagination, and implications for understanding immaterial substances.

50. The Two Acts of Reason and Understanding the Undivided #

This lecture explores Aristotle’s distinction between the two fundamental acts of reason: simple apprehension (understanding what a thing is) and composition/division (understanding truth and falsity in statements). Berquist examines how the intellect grasps undivided essences, the role of images in understanding, and how we know simple and immaterial things through negation. The lecture also addresses modern philosophical errors regarding the relationship between nature and reason, particularly how contemporary thinkers mistakenly separate reason from its natural foundations.

51. Potency and Actuality: Understanding Through Contraries #

This lecture explores how the human mind understands potency and actuality through its own nature as a being in potency for contraries and opposites. Berquist examines Aristotle’s teaching on how reason knows through experience of doubt and uncertainty, contrasts this with divine knowledge as pure act, and analyzes the distinction between the ability to know and actually knowing—illustrating how this principle applies to learning, ethics, and the fallacy of equivocation in reasoning.

52. Reason, Imagination, and the Soul as All Things #

This lecture explores the relationship between reason and imagination (phantasms), arguing that reason depends on images just as sensation depends on external sensibles. Berquist examines how human pleasures involving both sense and reason are distinctively human, contrasts theoretical and practical reason, and concludes with Aristotle’s remarkable claim that the soul is in some way all beings—not materially, but through the immaterial reception of forms.

53. The Soul as All Things: Knowledge, Form, and Phantasm #

This lecture explores Aristotle’s doctrine that the soul is in some way ‘all things,’ examining how the soul receives forms and species without material composition. Berquist contrasts this with Empedocles’ theory, analyzes the hand as an analogy for reason’s universality, and clarifies the critical distinction between imagination (phantasm) and thought through a detailed critique of Locke’s confusion between these powers.

54. The Powers of the Soul and Locomotion #

This lecture examines Aristotle’s inquiry into which power of the soul causes animals to move from place to place. Berquist critiques inadequate divisions of the soul (particularly Plato’s three-part division) and argues that two unified motive powers—desire and practical reason—work together to produce locomotion. The lecture emphasizes the role of imagination, appetite, and the desirable good as the principle of motion.

55. The Two Movers: Intellect and Desire in Local Motion #

Berquist examines Aristotle’s explanation of what causes local motion (movement from place to place) in living things. The lecture investigates why neither practical reason nor desire alone can account for motion, and how these two powers are unified through the desirable good—the end that is both understood and desired. The discussion explores the nature of practical versus theoretical reason, the problem of contrary desires in humans, and how temporal awareness creates the possibility of internal conflict between reason and sense appetite.

56. Animal Motion, Desire, and the Desirable Good #

Berquist examines Aristotle’s explanation of what moves animals from place to place, arguing that both imagination (or reason) and desire are necessary movers, unified by the desirable good as an unmoved mover. He explores how humans uniquely possess temporal consciousness that allows them to distinguish between what is good in some way versus simply good, and how failure to make this distinction leads to choosing apparent goods over true goods. The lecture critiques Plato’s three-part soul division while explaining the concupiscible and irascible appetites, and demonstrates how sense desire operates only on the immediate present whereas reason can look before and after in time.

57. Deliberation, Goods of the Soul, and the Application of Universals #

This lecture examines how deliberative imagination works in practical reasoning—particularly the need for a third measuring standard when choosing between two goods. Berquist connects this to Socrates’ division of human goods (soul, body, exterior) and explores why the goods of the soul are superior. The lecture culminates in a crucial analysis of how universal moral principles must be applied to particular situations, using abortion as a contemporary example of how people fail to apply universals correctly.

58. The Order of Powers in the Soul and Four Senses of Priority #

This lecture explores Aristotle’s doctrine of the order among the powers of the soul (nutritive, sensitive, and rational), with particular emphasis on understanding the four distinct senses of ‘before’ or priority: temporal, existential/being, rational discourse, and excellence/goodness. Berquist demonstrates how confusion between these senses leads to common logical fallacies, and applies this framework to analyze the relationship between necessity and excellence in practical reasoning.

59. Touch as the Foundational Sense and Animal Life #

This lecture examines Aristotle’s argument that the sense of touch is necessary for all animal life, while other senses exist for well-being rather than survival. Berquist explores why simple bodies (fire, air, earth) cannot possess animals, how the sense organ requires a mean between extremes, and the hierarchy of senses from touch through taste to the distance senses (sight, hearing, smell). The lecture emphasizes touch as the sense of certitude and interior knowledge, contrasting it with the higher senses of beauty.

60. Music, Beauty, and the Spiritual Senses #

This lecture explores the relationship between the senses and spiritual perception, focusing on why sight and hearing are considered more ‘spiritual’ than touch, taste, and smell. Berquist discusses Hegel’s ordering of the fine arts, the power of music in forming virtue and vice, and the distinction between poetry and psalms—arguing that music represents emotions partaking of reason and therefore stands closer to thought than sensory perception alone.

61. The Soul’s Nature: Essence, Powers, and Operations #

This lecture introduces Thomas Aquinas’s treatment of the human soul in Summa Theologiae I, Questions 75-89, focusing on the threefold division of spiritual substances (essence, powers, operations) and the methodological challenge of knowing the soul. Berquist discusses how we come to know the soul through its operations first, then its powers, and finally its nature—a reversal of the pedagogical order Thomas employs. The lecture also addresses two major pre-Aristotelian theories of the soul (the Pythagorean harmony view and the Platonic substantial view) and previews Aristotle’s synthetic account of the soul as a substantial form.

62. The Soul Is Not a Body: Refuting Materialist Theories #

Berquist examines Thomas Aquinas’s defense of the immaterial nature of the human soul against objections claiming the soul must be a body. Through analysis of form and matter, act and potency, and the distinction between moved and unmoved movers, the lecture demonstrates why the soul cannot be corporeal. The discussion includes historical context from ancient Greek philosophers and their materialist misconceptions about the soul’s nature.

63. The Soul is Not a Body but Its Form #

Berquist addresses Thomas Aquinas’s refutation of the ancient materialist opinion that the soul is a body. The lecture examines why ancient philosophers held this view (inability to transcend imagination), presents three major objections based on motion, knowledge, and contact, and explains Thomas’s positive solution: the soul is the act or form of a living body, not a body itself. The discussion emphasizes the distinction between matter and form and the principle that not every mover must itself be moved.

64. The Subsistence of the Human Soul #

This lecture examines whether the human soul is something subsisting—having existence by itself rather than merely in the body. Berquist presents Thomas Aquinas’s three main objections to the soul’s subsistence, then develops the central Thomistic argument that reasoning from the soul’s immaterial operation (understanding universals) to its independent mode of being. The lecture emphasizes the distinction between substantial and accidental forms, showing why the soul’s status as a substantial form is crucial for establishing its subsistence.

65. The Immateriality of Reason and Brain-Thought Relationship #

This lecture examines how the human intellect/reason is immaterial by analyzing its universal knowledge of bodies and its non-continuous mode of understanding. Berquist addresses the common objection that brain damage interferes with thinking, clarifying the distinction between the brain as an organ (on the side of the organ) versus brain interference occurring on the side of the object (imagination). Through logical analysis and concrete examples, he demonstrates why materialism’s conclusion that ’the brain is the organ of thought’ commits the fallacy of affirming the consequent, and why understanding actually depends on imagination only as its object, not as its bodily organ.

66. The Subsistence of Animal Souls and the Distinction Between Sensing and Understanding #

This lecture examines Article 3 of Aquinas’s treatment of the soul, addressing whether brute animal souls are subsistent (able to exist independently). Through careful analysis of Platonic and Aristotelian positions, Berquist argues that while the human soul is subsistent because understanding operates without bodily involvement, animal souls are not subsistent because all their operations (sensing and movement) necessarily involve bodily change. The lecture emphasizes that truth lies between two extremes: between those who deny any soul is subsistent and those who claim all souls are subsistent.

67. Is the Soul Man? Soul and Body Composition #

This lecture examines whether the soul alone constitutes the human person (Article 4, Question 75 of Aquinas’s Summa Theologiae). Berquist argues against the Platonic position that the soul is man, using the principle that what performs all operations of a thing is that thing itself. Since sensing requires bodily change and the soul cannot perform sensing operations alone, man must be understood as a composite of soul and body, not the soul in isolation.

68. Matter, Form, and the Immateriality of the Soul #

This lecture examines whether the human soul possesses matter and defends the immateriality of the understanding soul through Thomistic metaphysics. Berquist addresses objections claiming the soul must have matter, clarifies the equivocal use of ‘receive’ in material versus immaterial contexts, and explains how the soul’s capacity to understand universal forms demonstrates its independence from material composition. The lecture connects principles of act and potency, form and matter, to both angelic and human intellectual operations.

69. The Incorruptibility of the Human Soul #

This lecture examines Thomas Aquinas’s argument that the human soul is incorruptible, focusing on the distinction between corruption per se and per accidens, and demonstrating why a subsisting form cannot cease to exist. Berquist systematically addresses objections from Scripture and reason, establishing that the soul’s unique operations (understanding and willing) prove its independent subsistence and therefore its immunity from corruption.

70. The Incorruptibility of the Human Soul #

This lecture explores Thomas Aquinas’s arguments for the incorruptibility of the human soul, focusing on the role of contrariety in corruption, the distinction between subsistent and accidental forms, and the natural desire for eternal existence as a sign of the soul’s immortality. Berquist demonstrates how the understanding soul’s freedom from contrariety, unlike material things, proves it cannot be corrupted by its contrary, and how humanity’s rational grasp of existence across time grounds a natural desire for perpetual being.

71. Lowest Species and Diverse Operations: Soul and Angel #

This lecture explores whether the human soul and angels are of the same species, examining the nature of understanding in both substances. Berquist analyzes the concept of lowest species through geometric and artistic examples, then applies this framework to argue that despite both being understanding substances, the soul and angel differ fundamentally in their operations and thus in species. The discussion emphasizes that in immaterial substances, numerical diversity requires specific diversity, and that matter is the only principle allowing multiple instances of one form.

72. The Union of Soul and Body: Form and Matter #

This lecture examines Thomas Aquinas’s Question 76 on the union of the intellectual soul to the body, focusing on whether the intellectual principle is united to the body as a form. Berquist outlines the eight articles to be addressed, explains the concept of principium (principle/beginning) through its six meanings, and introduces the fundamental objection that an immaterial power (understanding) cannot belong to a material form. The lecture emphasizes etymological analysis of key terms and their philosophical implications, drawing extensively on Aristotle’s teaching on the soul.

73. The Soul as Form of the Body: Thomas’s Resolution #

This lecture presents Thomas Aquinas’s defense of the Aristotelian thesis that the intellectual soul is the form of the human body, addressing six major objections that seem to prove the soul cannot be form of a body given that understanding is not a bodily operation. Berquist explains Aristotle’s fundamental principle that ’that by which something first operates is the form’ and shows how the soul’s subsistence and non-immersion in matter can be reconciled with its role as the body’s form.

74. The Soul as Form of the Body: Thomas’s Demonstration #

This lecture presents Thomas Aquinas’s synthesis of Aristotle’s doctrine that the soul is the form of the body, addressing the apparent paradox that the human soul has immaterial operations (understanding and willing) while being united to matter as its form. Berquist develops three complementary demonstrations: from Aristotle’s principle that the soul is that by which we live, sense, move, and understand; from the refutation of alternative explanations (including Averroist and Cartesian positions); and from the nature of human species. The lecture establishes that the human soul is unique in being subsistent (having existence by itself) while remaining the form of a body.

75. Mystical Knowledge, Charity, and the Multiplicity of Souls #

This lecture explores two distinct ways of judging about divine things: through the gift of wisdom via charity and mystical experience, and through doctrinal study. Using St. Teresa of Avila as a primary example, Berquist examines how mystical knowledge involves knowing God through loving Him rather than through intellectual comprehension alone. The lecture then transitions to addressing the Averroist objection that there cannot be many human souls of the same kind, defending the Thomistic position that the soul’s proportion to a particular body grounds its numerical distinction without requiring matter to be the cause of individuation.

76. The Unity of the Intellect Against Averroism #

This lecture defends Thomas Aquinas’s position that each individual human being has his own intellect against the Averroist claim that one universal intellect serves all men. Berquist explains why the diversity of phantasms (mental images) in different minds does not entail a diversity of understandings, and demonstrates through geometric and sensory examples that one understanding can be grasped by many minds while remaining numerically one. The lecture addresses objections from immaterial substance theory and clarifies how the soul’s proportionality to the body explains the multiplication of individual souls.

77. The Unity of the Soul: One Form or Multiple Souls #

This lecture addresses the central question of whether the human soul is a single substantial form or multiple distinct souls (vegetative, sensitive, and rational). Berquist presents the Platonic objection that different, incorruptible and corruptible powers require different souls, then develops Thomas Aquinas’s Aristotelian response: the rational soul is the single substantial form of the body with multiple powers. The lecture emphasizes the metaphysical principle that a thing has both being and unity from the same form, and explores how this applies to understanding the human composite.

78. Substantial Form, Unity of the Soul, and Per Se Predication #

This lecture explores the distinction between substantial and accidental forms, arguing for the unity of the human soul against Platonic and Averroist positions that posit multiple souls. Berquist defends Thomas Aquinas’s Aristotelian account through three main arguments: the unity of being, the analysis of per se predication (especially in the second mode), and the empirical observation that intense operations of one power impede others. The lecture also examines the two modes of per se predication and their logical and metaphysical implications.

79. The Unity of the Soul and Spirit versus Soul in Scripture #

This lecture addresses Thomas Aquinas’s defense of the unity of the human soul against the Platonic heresy of multiple souls, culminating in an analysis of biblical texts that distinguish between ‘spirit’ (pneuma) and ‘soul’ (psyche). Berquist demonstrates that these scriptural terms refer to the same unified soul understood from different perspectives—the soul as animating the body versus the soul as possessing immaterial powers of reason and will. The lecture integrates Thomistic metaphysics with exegetical analysis of key passages including the Magnificat, 1 Thessalonians 5:23, and Christ’s words in Gethsemane.

80. The Soul as Substantial Form and the Unity of Man #

This lecture examines Thomas Aquinas’s treatment of whether man possesses multiple substantial forms or one unified soul. Berquist explores the Thomistic argument that the rational soul, as the substantial form of the body, necessarily contains and perfects the operations of lower forms (vegetative and sensitive), making man a unified being rather than a composite of distinct substances. The lecture addresses objections from medieval philosophers and clarifies the metaphysical principles underlying the doctrine of the soul’s unity.

81. Being Simply and Being in Some Way: The Fundamental Distinction #

This lecture explores the critical distinction between being simpliciter (being simply, without qualification) and being secundum quid (being in some qualified or diminished way). Berquist demonstrates how this distinction applies across two major divisions of being: substance/accident and act/potency. The lecture uses concrete examples and the fallacy of confusing these modes to show how this distinction is foundational to all philosophical inquiry and resolves apparent contradictions in epistemology and metaphysics.

82. Hope as a Theological Virtue: Definition and Distinctions #

This lecture examines hope as a theological virtue, breaking down its definition into six constituent parts as presented in the Catechism of the Catholic Church. Berquist explores how hope differs from faith and charity, analyzes its relationship to happiness and desire, and connects hope to prayer, particularly the Our Father and the Beatitudes. The lecture also employs the third and fourth tools of dialectic to compare hope with natural desires like wonder and the natural desire for happiness.

83. The Soul’s Union with Body and Accidental Dispositions #

This lecture explores whether accidental dispositions (qualities like hot/cold, wet/dry, and quantity) serve as intermediaries between the human soul and body. Berquist argues that the understanding soul is united to the body as its substantial form directly, without any accidental mediation, and refutes objections based on Platonic and other theories. The lecture emphasizes the metaphysical distinction between substantial and accidental being, illustrated through the principle that being simply (simpliciter) precedes being in some qualified way (secundum quid).

84. The Soul’s Union with the Body Without Intermediary #

This lecture addresses the seventh article of Thomas Aquinas’s treatment of how the soul unites with the body, specifically refuting the objection that an intermediary body is necessary for this union. Berquist clarifies the distinction between quantitative parts and essential parts (matter and form), demonstrating through multiple examples that the soul, as substantial form, unites immediately with the body as act to potentiality, requiring no mediating substance. The lecture also explores the equivocation of the word ‘part’ and critiques various false theories, including Platonic positions positing incorruptible intermediate bodies and celestial light as mediators.

85. The Whole Soul in Each Part of the Body #

This lecture explores Article 8 of Thomas Aquinas’s treatment of the soul-body union, focusing on Augustine’s remarkable claim that the whole soul exists in the whole body and simultaneously in each part of the body. Berquist works through Aquinas’s responses to apparent objections from Aristotle, distinguishing between the soul as a mover (present primarily in one part) and the soul as substantial form (present throughout). The lecture carefully distinguishes three types of wholeness—quantitative, definitional/essential, and potential—to resolve the seeming contradiction between Augustine’s insight and Aristotle’s observations about bodily organization.

86. Wholes and Parts: The Soul’s Presence in the Body #

This lecture examines how the soul, as a substantial form, can be wholly present in the whole body and in each part of the body without being divisible like quantitative wholes. Berquist uses Aristotle’s and Thomas Aquinas’s analysis of different kinds of wholes (quantitative, essential, definitional, and potential) to resolve apparent contradictions and clarify the soul’s relationship to bodily organs and their specific powers.

87. The Soul’s Essence and Its Powers #

This lecture examines whether the essence of the soul is identical to its powers, a fundamental question in understanding the nature of the human soul. Through careful analysis of potency and act, Berquist demonstrates why the soul’s essence must be distinct from its operative powers, drawing on Aristotelian metaphysics and Thomistic theology. The discussion includes Augustine’s doctrine of the soul as a potential whole present in the whole body and each of its parts.

88. Powers of the Soul: Essence, Accidents, and Natural Properties #

This lecture addresses Thomas Aquinas’s responses to objections regarding whether the powers of the soul are identical to its essence or constitute accidental properties. Berquist carefully distinguishes between accidents in the strict sense (as opposed to substance) and properties in Porphyry’s sense (as natural effects flowing from essence), explaining how the powers of the soul occupy a middle ground as natural properties. The discussion integrates Aristotelian metaphysics, Augustine’s theology, and complex examples from geometry and natural philosophy to clarify how substantial and accidental forms relate to operation and action.

89. Powers of the Soul Distinguished by Acts and Objects #

This lecture explores Thomas Aquinas’s account of how the powers (abilities) of the soul are distinguished from one another through their characteristic acts and formal objects. Berquist examines the philosophical problem of translation (potentia, dunamis), the relationship between active and passive powers, how objects function differently as moving causes versus ends, and why contraries and identical objects can pertain to different powers.

90. The Fallacy of the Accident and Per Se Distinctions #

This lecture explores the logical fallacy of the accident (fallacia accidentis), examining how accidental properties are mistakenly treated as essential to a thing’s nature. Berquist demonstrates through various examples—from geometry and malaria to drama and foreign language instruction—how to distinguish between per se (essential) and per accidens (accidental) differences. The discussion connects to the principle that powers are distinguished by their objects only insofar as those objects relate per se to the power, not accidentally.

91. Order Among Powers of the Soul #

This lecture examines the threefold order among the powers of the soul: the order of nature (perfection), the order of generation (time), and the order of objects. Berquist explores how higher powers direct and command lower powers, while lower powers dispose for higher ones, using both philosophical arguments and practical examples from human development and education. The lecture also addresses objections about whether powers divided from a common genus can have order among themselves, drawing on Aristotle’s comparison of soul powers to geometric figures.

92. The Ambiguity of ‘Powers of the Soul’: Subject vs. Source #

This lecture explores the ambiguity in the phrase ‘powers of the soul,’ examining how ‘of’ can mean either ‘powers whose subject is the soul’ or ‘powers whose origin/source is the soul.’ Berquist analyzes this distinction through the lens of Thomistic philosophy, clarifies how different powers relate to body and soul, and demonstrates how understanding this linguistic distinction illuminates both philosophy and theology, including scriptural interpretation and the doctrine of the Incarnation.

93. The Soul’s Powers: Substance, Form, and Natural Emanation #

Berquist explores how the powers of the soul flow from its essence, defending this thesis against three major objections. The lecture examines the soul as a substantial form (rather than either a complete substance or an accidental form), establishes the distinction between substantial and accidental forms, and explains the natural emanation of powers from the soul’s nature through geometric analogies. Central to the discussion is understanding that powers are proper accidents that necessarily follow from what the soul is, not through motion or change but through natural resulting.

94. Grace, Theological Virtues, and the Powers of the Soul #

This lecture explores the relationship between sanctifying grace and the theological virtues (faith, hope, and charity), establishing an analogy with how the powers of the soul flow from the soul’s essence. Berquist explains that just as reason and will naturally proceed from the soul, the theological virtues proceed from grace in the soul into its powers. The lecture then begins examination of Article 7 on whether one power of the soul proceeds from another, introducing the Aristotelian distinction between different senses of ‘before’ and causality.

95. The Multiple Senses of ‘Before’ and Causation #

This lecture explores the four distinct senses of the word ‘before’ (temporal, being, rational discourse, and perfection/goodness) and how they apply to understanding causation. Berquist demonstrates how equivocation between these senses leads to common philosophical errors, particularly in arguments about the relationship between breathing and philosophizing, and how Thomas Aquinas uses this distinction to explain the order of the soul’s powers. The lecture emphasizes that one cannot validly argue from one sense of ‘before’ to another, and illustrates this principle through linguistic analysis, practical examples, and an extended critique of Feuerbach’s confused reasoning about infinity and the divine.

96. Powers of the Soul: Their Origin, Order, and Persistence #

This lecture examines whether the powers of the soul flow from the soul itself, whether one power can proceed from another, and crucially, which powers remain in the separated soul after bodily death. Berquist works through Thomas Aquinas’s treatment of these questions, distinguishing between intellectual powers (understanding and will) that remain in act, and sensitive and vegetative powers that remain only as roots or principles. The lecture explores the equivocation of key terms like ‘memory’ and ‘joy,’ clarifying how emotional names are borrowed to describe acts of the will rather than bodily sensations.

97. The Five Genera of Powers of the Soul #

This lecture examines Thomas Aquinas’s distinction of five genera of powers of the soul (vegetative, sensitive, appetitive, locomotive, and intellectual) and explains why there are five powers but only three souls and four grades of life. Berquist clarifies the relationships between these powers, resolves apparent contradictions in how they are classified, and explores how appetite necessarily accompanies knowing powers rather than constituting a separate level of life.

98. Three Souls, Five Powers, and Four Grades of Life #

Berquist resolves the apparent contradiction between Thomas Aquinas’s distinctions of three souls, five genera of powers, and four grades of life. The lecture explores how souls are distinguished by three distinct ways of rising above mere bodily matter: the vegetative soul (using bodily qualities intrinsically), the sensitive soul (receiving sensible forms immaterially), and the rational soul (operating entirely without bodily organs). The apparent excess of five powers is reconciled by showing that appetitive powers necessarily accompany knowing powers, while locomotive power does not constitute a distinct transcendence of matter.

99. The Three Powers of the Vegetative Soul and Their Theological Significance #

This lecture examines Thomas Aquinas’s distinction of the three powers of the vegetative (living) soul: the generative, growing, and nutritive powers. Berquist addresses objections to this division, explains why generation is the most perfect of these powers, and develops the theological application of these powers to the three sacraments of initiation (Baptism, Confirmation, and Eucharist). The discussion emphasizes how the generative power approaches the dignity of the sensitive soul by extending beyond one’s own body, and explores the profound philosophical and theological significance of reproduction as the mortal striving to be like God.

100. The Five Exterior Senses: Distinction and Principle #

This lecture addresses why there are exactly five exterior senses and what principle explains their distinction. Berquist covers three major objections to the traditional enumeration of senses, examining the relationship between sensible qualities and other accidents, and establishes that senses are distinguished by the diverse ways exterior things can act upon them. The discussion introduces the crucial distinction between natural (material) and spiritual (immaterial) reception of forms.

101. Spiritual Reception and the Hierarchy of the Five Senses #

This lecture explores Thomas Aquinas’s distinction between spiritual (immaterial) and natural (material) reception of sensible forms, establishing why this distinction is essential to understanding sensation. Berquist develops the hierarchy of the five senses according to their degree of spirituality, from sight (most spiritual) through hearing, smell, taste, to touch (most material), explaining how this hierarchy reflects the metaphysical nature of each sense’s operation and connecting it to the human appreciation of beauty versus bodily pleasure.

102. Interior Senses and Animal Cognition #

This lecture examines Thomas Aquinas’s account of the four interior senses—common sense, imagination, estimative power, and memory—as powers of the sensitive soul that enable animals to perceive and retain knowledge beyond what the exterior senses provide. Berquist explores how these powers distinguish humans from other animals, particularly through the cogitative power (particular reason) and reminiscence, and addresses objections about whether such powers are necessary or if they represent genuinely distinct faculties.

103. Understanding as a Power of the Soul #

Berquist defends Thomas Aquinas’s position that understanding (intellect) is a power or ability of the soul, not its essence. Through the principle of proportionality—that being relates to nature as doing relates to ability—he argues that since creatures do not have identical being and understanding, they cannot have identical nature and ability to understand. He contrasts this with God, who is pure act where being and understanding are one, and applies similar reasoning to the will and other powers of the rational soul.

104. Love as Will, Not Emotion: Divine and Human Love #

This lecture explores the fundamental distinction between love as an emotion (a bodily feeling) and love as a chosen act of the will. Berquist examines how God’s love differs from human love in kind: God’s love is merciful (owed to no one), while human love of God is just (a debt we owe). The lecture extends into broader philosophical themes about the superiority of intellectual pleasures over bodily pleasures, the relationship between reason and desire, the nature of understanding versus potency and act, and the role of contradiction in discovering truth.

105. Understanding as Passive Power and the Agent Intellect #

This lecture explores whether understanding is a passive power and establishes the necessity of positing an agent intellect in human cognition. Berquist distinguishes three senses of ‘suffering’ or ‘undergoing’ (passio) in Latin and Greek philosophy, arguing that the understanding is passive only in the third, most broad sense—receiving intelligible forms that perfect rather than harm it. The lecture contrasts Platonic and Aristotelian approaches to explain why an active power of the intellect is necessary to make potentially intelligible things actually intelligible, and defends the agent intellect as a power of the human soul rather than a separate substance.

106. The Active Intellect as a Power of the Soul #

This lecture examines whether the active intellect (intellectus agens) is a power of the human soul or a separated substance. Berquist defends the Thomistic position against Averroist and Neoplatonic objections, arguing that the active intellect must be a power of the soul derived from God. The lecture addresses the apparent contradiction between the soul being in potency (to intelligible forms) and in act (as immaterial), and explains how the active intellect makes sensible forms actually intelligible through abstraction.

107. The Agent Intellect and the Necessity of Abstraction #

This lecture addresses why an agent intellect is necessary for human understanding and responds to objections claiming that the possible intellect alone suffices. Berquist defends Thomas Aquinas’s position that the agent intellect is a power of the human soul (not a separated substance) and explains its role in abstracting universal, immaterial forms from material phantasms. The lecture also connects the agent intellect to divine illumination through Scripture, particularly James 1:17 on God as the ‘Father of Lights.’

108. The Agent Intellect: Unity and Multiplicity #

This lecture examines whether the agent intellect is numerically one in all humans or multiplied according to individual souls. Berquist explores three key objections—that separated realities should not be multiplied, that what causes unity must itself be one, and that universal agreement on first principles suggests a single agent intellect—and defends Thomas Aquinas’s position that each human soul possesses its own agent intellect as a power, while maintaining metaphysical unity through participation in divine light and shared human nature.

109. The Agent Intellect, Universals, and the Danger of Imagination #

This lecture explores how the agent intellect abstracts universals from particular sensory images through the process of experience and memory. Berquist emphasizes the dangers of resolving understanding to imagination when dealing with immaterial realities like angels, the soul, and God, using detailed examples from logic and metaphysics to show how modern thinkers err by confusing classes with universals and by attempting to imagine what cannot be imagined.

110. Intellectual Memory and the Retention of Forms #

This lecture examines whether memory can exist in the intellectual part of the soul, distinct from sensory memory. Berquist defends Thomas Aquinas’s Aristotelian position against Avicenna’s objection that the intellect cannot retain understandable forms. The core argument centers on the principle that what is received is received according to the mode of the receiver, and the application of this principle to the immaterial intellect’s stable preservation of universal forms.

111. Eternity, Time, and the Divine Now #

This lecture explores the classical definition of eternity as ‘perfect possession of life without end,’ examining how it contrasts with time through a series of negations. Berquist discusses the fleeting character of the temporal now versus the eternal now, the relationship between natural and supernatural desires, and how the beatific vision represents the perfection of eternal life. The lecture also addresses how angels and humans in heaven will possess both morning and evening knowledge simultaneously.

112. Intellectual Memory and the Unity of Understanding #

This lecture addresses whether intellectual memory constitutes a separate power of the soul from understanding, examining Augustine’s trinitarian psychology and resolving apparent conflicts with Peter Lombard’s interpretation. Berquist clarifies that memory in the intellectual order represents habitual retention of intelligible forms by a single power, contrasting this with sensory memory where bodily nature necessitates distinct retentive powers. The discussion establishes key metaphysical principles about how forms are received and retained according to the mode of the receiver.

113. Reason and Understanding: Powers or Acts of One Power? #

This lecture addresses whether reason (ratio) and understanding (intellectus) are two distinct powers of the soul or acts of a single power. Berquist explores Thomas Aquinas’s position that they are the same power distinguished by their modes of operation, using the fundamental proportion that reason is to understanding as motion is to rest. The lecture examines how natural understanding (nous) precedes and grounds reasoned-out understanding (episteme), and considers objections from Augustine, Boethius, and John Damascene.

114. Higher and Lower Reason: Unity of Power and Distinction of Acts #

This lecture examines Augustine’s distinction between higher and lower reason, arguing that they constitute not two separate powers but rather two different operations of the same rational power. Berquist explores how reason relates to both eternal and temporal knowledge, clarifies the Aristotelian distinction between necessary and contingent knowledge, and introduces the important logical concept of equivocation by reason—how a single name can be applied to two different things based on perfection or addition.

115. Higher and Lower Reason: Unity of Powers Through Diverse Acts #

This lecture examines Augustine’s distinction between higher reason (directed toward eternal things) and lower reason (directed toward temporal things), and responds to objections claiming these must be different powers. Thomas Aquinas argues they are one power distinguished by their acts and habits, not by distinct powers. The lecture explores how reason knows both necessary and contingent truths through a single intellectual power, using examples from geometry, medicine, politics, and dialectical reasoning to illustrate the relationship between reason, understanding, and the modes of knowing.

116. Intelligentsia, Understanding, and the Acts of Reason #

This lecture explores the distinction between intelligentsia and intellectus (understanding/intellect) as different acts of the same power rather than diverse powers. Berquist examines how the Latin term intelligentsia properly signifies the act of understanding itself, drawing on Thomas Aquinas’s commentary on the Liber de Causis and Augustine’s De Spiritu et Anima. The lecture addresses problems of translation between Greek, Latin, and English, particularly how different languages make explicit distinctions that others obscure, and illustrates how understanding can be distinguished from mere thinking through linguistic analysis and concrete examples.

117. The Speculative and Practical Intellect #

This lecture examines Thomas Aquinas’s analysis of the distinction between the speculative (theoretical) and practical (doing) intellect, arguing they are not diverse powers but rather the same intellectual power ordered toward different ends. Berquist defends this unity against three major objections and uses concrete examples (the eye, the ear) to clarify how a single power can serve both contemplative and action-oriented purposes. The lecture also opens with an extended discussion of humility and the four species of pride, establishing the theological context for understanding how we properly receive divine grace.

118. Truth, Good, and the Virtues of Reason #

This lecture explores the relationship between truth and goodness as objects of intellect and will, arguing that they include rather than exclude each other. Berquist examines how the same power of reason can be ordered to different ends (speculative understanding vs. practical direction of action), and introduces the broad meaning of virtue as any disposition that makes a thing and its own act good, before moving toward understanding human virtue in reason.

119. The Virtues of Reason: Speculative and Practical #

This lecture explores the division of intellectual virtues into speculative (contemplative) and practical (doing) reason, grounded in their distinct ends: understanding truth versus directing action. Berquist explains how virtue perfects a power with respect to its end, and illustrates this principle through the five virtues of reason: natural understanding (intellectus), science (scientia), wisdom (sophia), prudence (phronesis), and art (technē). The lecture emphasizes that speculative and practical reason are not different powers but the same rational power ordered to different ends.

120. Synderesis as Natural Habit and Reason’s First Principles #

This lecture explores the nature of synderesis as a natural habit rather than a distinct power in practical reason. Berquist addresses objections that synderesis is a special power and clarifies how synderesis relates to reason as nature versus reason as reason. The discussion parallels the structure of speculative reason, establishing that both speculative and practical reason naturally know first principles—the axioms in speculative reason and ‘do good and avoid evil’ in practical reason.

121. Synderesis and Conscience: Habit vs. Power vs. Act #

This lecture examines the nature of synderesis and conscience within Thomistic philosophy, distinguishing them from powers of the soul. Berquist explores how synderesis functions as a natural habit of practical reason containing the first principles of action, while conscience operates as an act applying knowledge to particular situations. The discussion draws on Aristotelian philosophy of nature, habit formation, and virtue, and addresses objections to these distinctions through careful analysis of the relationship between potency, act, and habitus.

122. Conscience as Act: Etymology, Functions, and Distinction from Synderesis #

This lecture explores Thomas Aquinas’s analysis of conscience, arguing that conscience is properly understood as an act rather than a power or habit. Berquist examines the etymological structure of the word ‘conscience’ (con + scientia), its three modes of application (testimony, judgment, evaluation), and clarifies the relationship between conscience as act and synderesis as the natural habit of practical reason. The lecture addresses objections through careful linguistic analysis and illustrates the doctrine with examples from Shakespeare, literature, and moral experience.

123. Figures of Speech in Scripture and Poetry #

This lecture explores rhetorical figures of speech—particularly metonymy and synecdoche—as they appear in Scripture and poetry. Berquist examines how understanding these figures is essential for correctly interpreting texts like the Gospel of John and Shakespeare’s sonnets, and discusses why philosophers and theologians sometimes overlook the doctrine of these figures despite their prevalence in authoritative texts.

124. Appetite as a Distinct Power of the Soul #

This lecture examines whether appetite (appetitus) constitutes a separate genus of powers of the soul distinct from other powers, and whether sense desire and intellectual desire are two different powers. Berquist develops the argument that knowing beings possess forms in a higher way than non-knowing things, and therefore possess inclinations and desires not found in non-knowing things. The lecture also addresses the distinction between natural desire (found in all things) and animal/elicited desire (following upon knowledge), and between sense appetite and will.

125. Intellectual Desire and the Application of Universal to Singular #

This lecture explores the distinction between sense desire and intellectual desire, demonstrating how intellectual desire grasps universal reasons for desiring or avoiding things. Berquist examines how universal principles must be applied to particular situations to move action, using examples from ethics, temptation, and moral decision-making. The lecture emphasizes that the will can desire immaterial goods like truth, wisdom, and God, which the senses cannot apprehend.

126. Sensuality as Desiring Power: Knowledge vs. Desire #

This lecture examines whether sensuality (sensualitas) is a knowing power or a desiring power, establishing it as fundamentally appetitive rather than cognitive. Through the distinction between knowing (which perfects by having the thing known within the knower) and desire (which perfects by moving toward the object), Berquist clarifies why sensuality is named from sensible motion. The lecture introduces the foundational contrast between knowledge and love, illustrating how opposites can be known together but cannot be loved together.

127. The Irascible and Concupiscible Appetites #

This lecture examines Thomas Aquinas’s doctrine of the two powers of sense desire: the concupiscible appetite (inclined toward agreeable things and away from disagreeable things) and the irascible appetite (concerned with resisting impediments and difficult goods/evils). Berquist explains why these are two distinct powers rather than one, how they relate to the estimative and cogitative powers, and presents the eleven emotions (six concupiscible, five irascible) that flow from these appetites. The discussion includes how these emotions function in human psychology and why the irascible is in some sense a higher power than the concupiscible.

128. Emotions, Rhetoric, Music, and the Obedience of Appetites to Reason #

This lecture explores the role of emotions in ethics, rhetoric, poetic science, and music, then examines whether the irascible and concupiscible appetites obey reason. Berquist discusses how sense desire can be moved by reason through the cogitative power and by the will, establishing the distinction between despotic rule (over the body) and political rule (over the appetites). The lecture emphasizes the importance of experience and habituation in training emotions, and discusses how music and literature serve as powerful tools for emotional formation.

129. Reason’s Rule Over the Emotions: Paternal vs. Despotic Rule #

This lecture explores how reason governs the passions and emotions through two distinct types of rule: despotic rule (as the soul dominates the body) and political or paternal rule (as reason should govern the irascible and concupiscible appetites). Berquist draws on Aristotle’s distinction from the Politics and Thomas Aquinas’s commentary to explain why emotions cannot be controlled like bodily members, yet must be trained through habituation, proper upbringing, and exposure to formative influences like music and literature.

130. Necessity and the Will: Freedom and Natural Inclination #

This lecture examines Thomas Aquinas’s treatment of whether the will necessarily wills whatever it wills, focusing on the crucial distinction between natural necessity and coercive necessity. Berquist explores how the will can be both naturally inclined toward happiness and remain free in choosing particular goods, drawing on Aristotelian distinctions between natural and rational powers. The lecture establishes that natural necessity—rooted in the will’s very nature—is compatible with freedom, whereas only external coercion destroys voluntariness.

131. The Will’s Necessity and Freedom in Willing Particulars #

This lecture explores whether the will wills things from necessity, examining Thomas Aquinas’s response to three objections claiming the will is necessarily moved by its object. Berquist develops a detailed analogy between the understanding’s relationship to first principles and the will’s relationship to beatitude, arguing that while the will necessarily wills happiness as its ultimate end, it does not necessarily will particular goods unless it perceives their necessary connection to happiness. The lecture emphasizes the distinction between natural necessity (which preserves freedom) and necessity of force (which contradicts it), and explores how reason’s capacity to consider multiple goods makes the will free regarding particulars.

132. The Will’s Necessity and the Intellect-Will Hierarchy #

This lecture explores whether the will necessarily wills anything, examining different types of necessity (natural, hypothetical, and coercive) and their compatibility with freedom. Berquist then transitions to the comparative nobility of the intellect and will, introducing the crucial distinction between simpliciter (simply) and secundum quid (in some respect) to resolve apparent contradictions about which faculty is higher. The discussion draws heavily on Thomistic philosophy and Aristotelian logic, with extensive use of examples and literary references to clarify abstract principles.

133. Fallacies of Speech and the Distinction Between Simply and In Some Respect #

This lecture examines two major fallacies outside of speech: the fallacy of equivocation (particularly regarding definitions) and the fallacy of confusing what belongs to something ‘simply’ (simpliciter) versus ‘in some respect’ (secundum quid). Berquist illustrates these distinctions through concrete examples and applies them to explain how people desire bad things, how the understanding and will relate to each other, and how knowledge can be both perfect and imperfect in different senses.

134. Whether the Will Moves the Understanding #

This lecture examines whether the will can move the understanding, resolving the apparent conflict between the understanding’s nobility and the will’s apparent command over it. Through careful analysis of equivocation in the term ’to move,’ Berquist explains how understanding and will move each other in different senses: the understanding moves the will as an end (formal cause), while the will moves the understanding as an efficient agent. The resolution hinges on recognizing that these powers, being immaterial and universally open, can contain each other’s objects and acts in a way material powers cannot.

135. The Irascible and Concupiscible in the Will #

This lecture examines whether the irascible and concupiscible powers—traditionally divided in sensory appetite—can be distinguished in the rational will. Berquist argues, following Thomas Aquinas, that while these powers are properly divided at the level of sense appetite, they are unified in the intellectual appetite (the will) because the will’s object is the universal good rather than particular sensible goods. The lecture explores how names and emotions are carried over from the sensitive to the rational order, and ultimately to divine attributes, with careful attention to what is lost and retained in this transposition.

136. Free Will, Divine Causality, and the Fifth Objection #

This lecture addresses the fifth major objection to human free will, which claims that man’s natural qualities determine what ends appear good to him, thereby eliminating genuine freedom. Berquist examines Thomas Aquinas’s distinction between natural and acquired qualities, showing how bodily dispositions incline without determining the will’s choice. The lecture explores how reason can resist bodily inclinations and how habits formed through repeated acts create moral responsibility, even when nature predisposes us toward certain emotions or desires.

137. Free Will as a Power: Nature and Objections #

This lecture examines whether free will (liberum arbitrium) is a power of the soul or a habit, using Thomistic analysis to address objections that free will is lost through sin, is merely an act rather than a power, or is determined by natural inclination. Berquist demonstrates how Thomas Aquinas resolves these objections by distinguishing between natural and acquired habits, and by clarifying how free will remains indifferent to choosing well or badly.

138. Free Choice, Divine Movement, and the Soul’s Knowledge #

This lecture concludes the discussion of free will and divine providence by addressing five major objections to human freedom, then transitions to an overview of Questions 84-89 on the soul’s operations and knowledge. Berquist systematically explains how Thomas resolves the apparent conflict between divine causality and human freedom, emphasizing that God moves the will according to its nature—freely. The lecture then provides a comprehensive framework for understanding how the soul knows bodily things, itself, and immaterial substances, both in this life and after death.

139. Whether the Soul Knows Bodies Through Understanding #

This lecture examines the central question of whether the soul can know material, changeable bodies through the intellect or only through the senses. Berquist traces the historical development from pre-Socratic flux philosophy through Plato’s theory of separated forms to Aristotle’s resolution, showing how Thomas Aquinas defends the possibility of intellectual knowledge of bodies by appealing to the principle that ‘whatever is received is received according to the manner of the receiver’ (quidquid recipitur, recipitur secundum modum recipientis).

140. How the Soul Knows Bodies: Against Empedocles and Plato #

This lecture examines how the immaterial soul can know material bodies, refuting the materialist positions of Empedocles and the recollectionist theory of Plato. Berquist defends the Aristotelian-Thomistic view that material things are known immaterially through intelligible species acquired via sensation and abstraction, establishing the fundamental principle that whatever is received is received according to the mode of the receiver.

141. Avicenna and Plato: Theories of Intelligible Forms #

This lecture examines Avicenna’s modification of Platonic theory regarding the source of intelligible forms, contrasting it with both Plato’s separated forms and Aristotle’s solution through the agent intellect as a power of the soul. Berquist walks through three objections supporting Avicenna’s position, then presents Thomas Aquinas’s refutation, focusing on why sensory experience remains necessary for human knowledge despite the immateriality of the understanding.

142. Knowledge, Reason, and the Eternal Reasons #

This lecture explores how human knowledge participates in divine knowledge through the natural light of reason. Berquist uses Heraclitus’s fragments on common reason to illustrate that truth is shared among all rational minds, connects this to Augustine’s reconciliation of Platonic and Aristotelian epistemology, and explains how the agent intellect abstracts universal concepts from sensible particulars while being itself a partaking of the eternal divine reasons.

143. Plato, Aristotle, and the Problem of Understanding Images #

This lecture explores how the human intellect understands material things, comparing Plato’s and Aristotle’s positions on the relationship between sense, imagination, and intellect. Berquist emphasizes that understanding requires turning to images (phantasms), clarifies that the brain is related to thought as object rather than organ, and demonstrates through logical analysis why brain injury interferes with thinking without proving the brain is the organ of thought.

144. Logic, Argument Structure, and Syllogistic Form #

This lecture examines the logical structure of arguments, particularly focusing on valid and invalid syllogistic forms. Berquist uses concrete examples to demonstrate how arguments can fail either through faulty logical form (conclusion does not follow necessarily) or through false premises (matter is bad), emphasizing that both valid form and true premises are necessary for a sound demonstration. The lecture includes discussion of the Prior and Posterior Analytics, induction, and the relationship between logical form and truth.

145. Abstraction, Matter, and the Knowledge of Material Things #

This lecture addresses the fundamental problem of how the human intellect can understand material things when matter seems essential to their definition. Berquist explores the distinction between two kinds of abstraction, the relationship between common and individual matter, and how the intellect relates to phantasms (images). The lecture extensively contrasts Platonic and Aristotelian approaches to universals, defending Aristotle’s position that universals exist only in the mind while corresponding to what is genuinely common in material reality.

146. Intelligible Forms and the Nature of Understanding #

This lecture examines Thomas Aquinas’s account of how intelligible forms function in human understanding. Berquist defends the Thomistic position that intelligible forms are ’that by which we understand’ rather than ’that which is understood,’ drawing parallels to sensible perception and refuting the Platonic error that universals exist as separate substances. The discussion addresses how the mind can know external reality through immaterial forms, and how universality arises as a mode of understanding rather than a mode of being.

147. Knowledge of Universals: Confused Before Distinct #

This lecture explores the order of human knowledge, demonstrating that we proceed from confused to distinct understanding, and from more universal to less universal concepts. Berquist examines the relationship between sensory and intellectual knowledge, the nature of universals as wholes and parts, and defends Aristotelian epistemology against Platonic realism and modern rationalist errors (Descartes, Spinoza, Hegel) that incorrectly generalize mathematical knowledge to all domains.

148. Understanding Multiple Things and Composition in the Mind #

This lecture explores whether the human understanding can grasp multiple things simultaneously, establishing that while God understands all things through one simple act, humans must understand things either confusedly as parts of a whole or distinctly through separate acts. Berquist examines the nature of intelligible forms, the discrete (rather than continuous) character of thought, and how composition and division necessarily characterize human understanding as it proceeds from potency to act.

149. Understanding, Composition, Division, and Truth #

This lecture explores the second act of the human intellect—composition and division—and its relationship to truth and falsity. Berquist explains why the human understanding necessarily operates through composition and division (unlike divine and angelic understanding), how this process relates to time and images, and defends the Thomistic position that the understanding cannot err in simple apprehension, only in composition/division. The lecture concludes with a sophisticated argument demonstrating that apparent mistakes in understanding are actually failures of distinct comprehension.

150. Understanding and Knowledge: Better Understanding and the Indivisible #

This lecture explores whether one person can understand the same thing better than another, how bodily disposition affects the quality of understanding, and the relationship between understanding the indivisible versus the divisible. Berquist examines Thomas Aquinas’s responses to objections about equality of understanding, the role of imagination and memory in intellectual operations, and the epistemological priority of the continuous over the absolutely indivisible in human knowledge.

151. Knowledge of Singulars and the Infinite #

This lecture examines two central questions from Thomas Aquinas’s Summa Theologiae Question 86: whether the human intellect can know singular material things, and whether it can know an infinity of things. Berquist explores the distinction between direct knowledge of universals and indirect reflective knowledge of singulars, addresses how practical intellect applies universal principles to particular actions, and clarifies the senses of infinity (potential vs. actual) in relation to human understanding.

152. Knowledge of Contingent and Future Things #

This lecture addresses whether the human intellect can know contingent things (those that can be or not be) and future things, exploring the distinction between knowing things in themselves versus in their causes. Berquist develops Thomas Aquinas’s position that contingent things are known indirectly through universal necessary reasons rather than directly as contingent, and that future things in themselves are known only to God through His eternal now, while humans can know future things through their causes with varying degrees of certitude depending on whether those causes produce effects necessarily or only for the most part.

153. The Soul’s Self-Knowledge Through Acts, Not Essence #

This lecture explores how the human soul knows itself, contrasting the soul’s self-knowledge with that of angels and God. Berquist examines the principle that things are knowable insofar as they are in act rather than in potency, and argues that the human soul, existing as pure potency in the order of understandable things, knows itself through its actualized acts rather than through its essence. The lecture also addresses the distinction between knowing that one has a soul and knowing the nature of the soul itself, and clarifies misconceptions about the brain’s relationship to thought.

154. Self-Knowledge of the Soul and Habits Through Acts #

This lecture explores how the human soul and intellectual habits come to know themselves, distinguishing between immediate knowledge of presence and the investigative knowledge of nature. Berquist contrasts the human intellect (which knows itself through acts) with divine and angelic intellects (which know themselves through their essence), and addresses how habits like faith are known through their characteristic operations rather than through direct intuition of their essence.

155. The Order of Knowledge and Self-Knowledge in the Human Mind #

This lecture examines how the human understanding knows objects, its own acts, and itself, following Aristotle’s principle that objects are known before acts and acts before powers. Berquist explores the distinction between knowing through essence (as angels do) versus knowing through acts (as humans do), the role of being and truth as common objects of the intellect, and how the principle ‘quod unum quod quae ilud magis’ applies to knowledge. The lecture also addresses how habits and powers are known through their acts rather than as objects in themselves.

156. Eternity, Self-Knowledge, and the Infinite in the Mind #

This lecture explores the nature of eternity as distinguished from endless time, examines how the human soul knows itself and its own acts, and addresses the problem of infinite regress in self-reflexive knowledge. Berquist uses Boethius’s definition of eternity, Aquinas’s treatment of the soul’s knowledge, and various logical sophistries to clarify how the mind can know itself without infinite regress, and how understanding and will relate to one another.

157. The Human Soul’s Knowledge of Immaterial Substances #

This lecture examines how the human soul can know immaterial substances (angels) during earthly life, drawing on Augustine and Aristotle. Berquist explores the relationship between material and immaterial knowledge, critiques the notion that the human mind should naturally understand angelic beings, and establishes that human understanding naturally orients toward material things, from which we ascend to immaterial knowledge through reasoning, negation, and causality. The discussion includes principles of education and development showing how what is most knowable in itself may be least known to us initially.

158. Knowledge of Immaterial Substances and the Agent Intellect #

This lecture examines whether the human intellect can understand immaterial substances (angels) in the present life, contrasting Platonic and Aristotelian approaches. Berquist presents and refutes Averroes’s theory that the agent intellect is a separated substance, establishing instead that the agent intellect is a power of the soul. The lecture explores how what is most knowable in itself may be least knowable to us, and clarifies that immaterial substances can only be known imperfectly through material things by way of negation and relation.

159. Knowledge of Immaterial Substances and God #

This lecture addresses whether the human understanding can know immaterial substances (angels) and God in this present life. Berquist examines objections claiming we can understand immaterial things through abstraction from material things, contrasts Platonic and Aristotelian approaches, and concludes that while we can achieve some imperfect knowledge of angels through material things (via negation and analogy), we cannot know God’s essence. The lecture emphasizes the crucial distinction between what is ‘more understandable in itself’ versus ‘more understandable to us,’ and explains how our knowledge is ordered through natural understanding rather than direct divine illumination.

160. The Separated Soul’s Knowledge and Understanding #

This lecture explores Question 89 of Aquinas’s Summa Theologiae on the knowledge of the separated soul—how the human soul understands after death when no longer united to the body. Berquist addresses whether the separated soul can understand at all, how it knows immaterial substances and natural things, and why the soul’s natural mode of understanding changes when separated from the body. The central insight is that the soul’s way of doing follows its way of being: as the soul’s mode of being changes at death, so too does its natural mode of understanding shift from turning toward images to turning toward actually understandable immaterial things.

161. The Separated Soul’s Knowledge of Substances and Natural Things #

This lecture examines whether the separated soul can understand both immaterial substances (angels) and natural things after death. Berquist works through Thomas Aquinas’s treatment of these questions, explaining how the soul’s mode of understanding changes when freed from the body—moving from knowledge through images to knowledge through forms divinely infused. The lecture explores the distinction between perfect knowledge of other human souls and imperfect knowledge of angels, and establishes that the separated soul has only confused, not particular, knowledge of natural things.

162. Knowledge of Separated Souls: Habits, Acts, and Distance #

This lecture examines whether the habits and acts of scientific knowledge acquired in earthly life persist in the separated soul after death, and whether local distance impedes such knowledge. Berquist works through Thomas Aquinas’s treatment of these questions, establishing that intelligible forms and habits remain in the separated understanding while sensory components are lost, and that the mode of understanding transforms from image-dependent to direct illumination by divine light. The lecture also addresses whether separated souls can know events occurring among the living.

163. Knowledge of the Separated Soul and the Dead #

This lecture examines how souls separated from the body—whether in purgatory or after death—can acquire and retain knowledge of earthly affairs. Berquist addresses objections concerning the dead appearing to the living, explores various modes by which separated souls receive information (through angels, demons, divine revelation, or newly arrived souls), and clarifies that separated souls lack natural knowledge of singular earthly events but may possess it through supernatural means. The discussion also touches on memory and knowledge retention after death, particularly in relation to natural knowledge and the limits of the separated soul’s understanding.