Natural Hearing (Aristotle’s Physics) #

A systematic study of Aristotle’s Physics and the foundations of natural philosophy. These lectures examine the progression from confused to distinct knowledge of nature, the four causes, the principles of change and motion, time and place, and the question of whether nature acts for an end.

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Lectures #

1. The Proenium and the Order of Natural Philosophy #

Berquist explores the structure of Aristotle’s Physics, distinguishing between the proenium (introductory section that prepares the way) and the main body of the work. He establishes the central argument that the confused precedes the distinct in human knowledge, and therefore the general precedes the particular. The lecture introduces the first kind of example demonstrating this principle through sensible composed wholes, particularly drawing from examples of taste, smell, and hearing to show how knowledge develops from indistinct to distinct understanding.

2. Knowledge from Confused to Distinct: Aristotle’s Epistemology #

Berquist examines Aristotle’s foundational principle that human knowledge naturally proceeds from the confused (indistinct) to the distinct, using three types of examples: sensible composed wholes, intelligible composed wholes, and more universal sensibles. He explores why what is more known to us is often less knowable in itself, and how this principle applies to all forms of education—physical, aesthetic, and moral. The lecture concludes by contrasting Aristotle’s epistemology with Descartes’ identification of certitude with clarity and distinctness.

3. Confused vs. Distinct Knowledge: Aristotle Against Descartes #

This lecture examines the fundamental disagreement between Aristotle and Descartes regarding the relationship between clarity/distinction and certitude in human knowledge. Berquist demonstrates through logical analysis and modern physics examples that Aristotle’s position—that confused (indistinct) knowledge is more certain than distinct knowledge—is correct, and that Descartes’ identification of certitude with clarity and distinction represents a foundational error with cascading consequences for epistemology and theology.

4. Equivocation, General/Particular Distinction, and Theological Knowledge #

This lecture addresses how equivocation—the use of a single word with multiple meanings—leads to apparent contradictions in Aristotle, particularly regarding the relationship between singulars and universals. Berquist clarifies that ‘particular’ has two senses (singular/individual vs. less universal) and ‘general’ has two senses (universal vs. more universal), resolving the sophistic objection that Aristotle contradicts himself. The lecture then applies this distinction to theology, arguing that knowledge of general concepts is more useful than particular knowledge because theology proceeds primarily through negation (via negativa), and negating the general is more effective than negating the particular.

5. Common and Private Experience in Natural Philosophy #

This lecture explores the distinction between common experience (which all humans have and cannot avoid) and private experience (which only some humans have), and how this distinction grounds the difference between natural philosophy and experimental science. Berquist explains why Aristotle’s eight books on natural hearing and three books on the soul require only common experience, while modern experimental sciences require private experience through specialized tools and experiments. The lecture connects this to the natural road of knowledge and demonstrates how knowledge based on common experience is necessarily more general than knowledge based on private experience.

6. Experience in Science and the Concept of Nature #

This lecture explores the distinction between common and private experience in experimental science versus philosophy of nature, examines how Heisenberg and other physicists understand the experimental method, and begins Aristotle’s definition of nature as an intrinsic principle. Berquist emphasizes how theology relies on common experience and the via negativa, and introduces the etymological roots of the word ’nature’ (phusis/natura) to ground understanding of natural philosophy.

7. Nature as Internal Cause: Definition and Distinction from Art #

This lecture explores Aristotle’s definition of nature as an internal principle of change and rest, developing the concept through five component parts. Berquist carefully distinguishes nature from art (artificial causation) and custom through concrete examples, emphasizing that nature is what is ‘first’ responsible for a thing’s operations and exists ‘as such’ rather than ‘by happening.’ The lecture demonstrates why understanding nature’s internal character is foundational to natural philosophy.

8. The Natural Road, Rhetoric, and the Mathematics-Nature Distinction #

This lecture explores why philosophers follow the natural road of knowledge (from senses through reason), examines rhetoric as an offshoot of logic and ethics, and addresses the central problem of how mathematics and natural philosophy relate to one another. Berquist explains Aristotle’s solution that the mathematician considers things in separation from matter while the natural philosopher considers them only as they exist in natural bodies, drawing on historical examples from Kepler and Einstein to illustrate this distinction.

9. The Central Question of Philosophy: Knowledge and Reality #

This lecture explores Aristotle’s solution to the relationship between mathematics and natural philosophy through an examination of the central question of philosophy: Does truth require that the way we know be the way things are? Berquist contrasts Aristotle’s negative answer with Plato’s affirmative answer, showing how different philosophical positions flow from answering this question differently, and demonstrating that we can know things truly in separation from their actual mode of existence without incurring falsity.

10. The Central Question of Philosophy and Knowledge #

This lecture explores the foundational question of philosophy: Does truth require that the way we know something must be the way it actually is? Berquist traces how different philosophers answer this question differently—Plato and the continental rationalists answering yes, Aristotle answering no—and shows how this single question generates vastly different philosophical systems (Spinoza, Hegel, Kant) and ultimately leads to pantheism or skepticism. The lecture defends the Aristotelian-Thomistic position that we can know things truly in ways they do not exist, using examples from mathematics, sense experience, memory, and divine knowledge.

11. Thales and Anaximander: The Beginning of Philosophy #

This lecture explores the first natural philosophers of Miletus, focusing on their inquiry into the arche (beginning or principle) of all things. Berquist examines Thales’s argument for water as the fundamental principle and Anaximander’s development of the concept of the apeiron (unlimited). The lecture demonstrates how philosophical reasoning about material causes develops from sensible experience and connects these pre-Socratic insights to later Aristotelian natural philosophy and Christian theology.

12. Law, Equivocation, and the Analogy of Terms #

This lecture explores how philosophical and scientific language develops through the process of borrowing words from their original contexts. Berquist examines how terms like ’law,’ ‘obedience,’ and ‘debt’ are transferred from human society and justice to describe natural phenomena, and how understanding this analogical process prevents logical fallacies like equivocation. The lecture emphasizes the importance of recognizing when words carry multiple meanings, illustrated through examples from Shakespeare, modern physics, and Thomistic philosophy.

13. The Milesians, Pythagoras, and Heraclitus: Matter, Form, and Change #

This lecture examines the pre-Socratic philosophers’ search for the first principle of all things, progressing from Thales, Anaximander, and Anaximenes’ material principles (water, the unlimited, air) through Pythagoras’s introduction of form as a mathematical cause, to Heraclitus’s emphasis on change, contradiction, and the mover. Berquist explores why increasingly thin and formless substances are better candidates for first matter, how mathematics reveals formal causation distinct from material causation, and how Heraclitus’s doctrine of flux introduces the problem of apparent contradiction in change.

14. Heraclitus, Change, and the Axiom of Contradiction #

This lecture examines Heraclitus’s philosophy of change and flux, focusing on the apparent contradictions inherent in change and how his insights relate to Parmenides’s axiom of contradiction. Berquist explores how change occurs between contraries, discusses the dichotomy between Heraclitus and Parmenides, and shows how Aristotle resolves their disagreement by distinguishing real from apparent contradictions. The lecture emphasizes the principle that reason seeks unity and how understanding change is fundamental to all philosophy.

15. Fire as First Matter and Mover: The Problem of the Cosmos #

This lecture examines Heraclitus’s proposal of fire as the first principle, analyzing why fire is superior to previous guesses (earth, water, air) yet remains inadequate as unlimited matter. Berquist explores the tension between fire’s function as both mover and matter, showing how this distinction anticipates later philosophical development and raises the fundamental problem: if mindless matter or mover is the origin of all things, how does the ordered cosmos (rather than chaos) exist? The lecture concludes by examining how modern physics (Einstein, Heisenberg) parallels this ancient insight, and how the problem necessitates introducing Mind as a cause.

16. God’s Five Attributes and the Natural Mind’s Inclination #

Berquist explores the five divine attributes found in Thomas Aquinas’s treatment of God’s substance: unity, simplicity, unchangeability, infinity, and perfection. He demonstrates how the first four of these attributes appear naturally in the human mind’s inclination toward first principles, as evidenced in ancient Greek philosophers and modern scientists. The lecture establishes how these natural inclinations prepare the mind to receive the theological reasons Thomas provides for God’s attributes, showing harmony between natural reason and revealed truth.

17. Empedocles: The Four Elements and Change as Mixture #

This lecture explores Empedocles’ revolutionary shift from monism to pluralism, arguing that multiple first matters (the four elements: earth, air, fire, and water) are necessary to account for the diversity of qualities in the universe. Berquist examines Empedocles’ either-or argument against single first matter, his use of opposite qualities (hot/cold, wet/dry) to distinguish elements, and his theory that all change is merely mixture and separation of eternal elements—a position that reduces all apparent qualitative change to local motion.

18. Empedocles: Elements, Love, Hate, and Order #

This lecture examines Empedocles’ response to monism through his theory of four elements (earth, air, fire, water) and his introduction of love and hate as cosmic moving causes. Berquist explores how Empedocles attempts to explain the apparent order in nature through random combinations and survival, contrasting this with Anaxagoras’ appeal to a greater mind. The lecture also addresses Empedocles’ epistemology—that the thing known must be in the knower—and its problems when conceived materially.

19. Anaxagoras on Matter, Mind, and Infinite Divisibility #

This lecture examines Anaxagoras’s theory of matter and mind, focusing on his principle that everything comes from everything through infinite divisibility and mixing/separation. Berquist explores how Anaxagoras attempts to preserve the Greek axiom that nothing comes from nothing by positing infinitely small pieces of all things in all things, and traces remarkable parallels between Anaxagoras’s ancient theory and twentieth-century elementary particle physics. The lecture also introduces Anaxagoras’s concept of mind (nous) as the unlimited, self-ruling principle that causes cosmic order through circular motion.

20. Relative Quantities, Descartes, and the Order of Learning #

This lecture explores the Aristotelian distinction between absolute and relative quantity, using ’large’ and ‘small’ as examples of relative predicates. Berquist examines how Descartes’s method of doubt relates to this framework, clarifies the proper epistemic ordering in philosophical learning (from what is more known to us toward what is less known), and contrasts how classical philosophers build cumulatively on their predecessors versus how modern philosophers often contradict without acknowledgment or reasoning. The lecture emphasizes the importance of following the natural order of learning and understanding the dependencies between foundational concepts like the three meanings of badness.

21. Anaxagoras’s Mind: Self-Rule, Separation, and the Ruling Principle #

This lecture explores Anaxagoras’s doctrine of mind (nous) as the fundamental ordering principle of reality, examining six key attributes of mind and resolving the apparent contradiction between mind’s self-ruling nature and the principle that a ruler must be separated from the ruled. Berquist demonstrates how Socratic epistemology—the separation of knowledge from ignorance—provides the key to understanding how mind governs itself, and traces the implications for logic, ethics, political philosophy, and natural philosophy.

22. The Mover and Matter: From Heraclitus to Quantum Theory #

This lecture traces the historical development of the concept of the ‘mover’ (efficient cause) in pre-Socratic philosophy, from Heraclitus’s unified fire to Anaxagoras’s separated mind (nous), showing how modern physics echoes these ancient problems. Berquist demonstrates parallels between ancient Greek thought and contemporary science (energy in physics, determinism in classical science, and indeterminacy in quantum theory), while examining how mathematical abstraction and democratic customs influence philosophical thinking about causation and necessity.

23. Democritus, Atomism, and the Problem of Change #

This lecture examines Democritus’s atomic theory as a response to the problem of change and motion in nature. Berquist explores Democritus’s thought experiment about the divisibility of matter, the meaning of the atom (ἄτομος) as the uncuttable fundamental unit, and the necessity of the void for motion. The lecture also discusses how modern physics replicates ancient atomistic assumptions and addresses the paradox that scientific observation relies on sense qualities while the mathematical description of nature excludes them entirely.

24. Hope and Fear in Philosophical and Spiritual Life #

This lecture explores the balance of hope and fear as necessary virtues in both the philosophical and spiritual life. Berquist examines how despair and excessive boldness represent opposite errors in responding to universal disagreement among philosophers, drawing on Thomas Aquinas’s teaching about hope in divine mercy balanced with fear of divine justice. The lecture emphasizes how spiritual directors and teachers must discern what each person needs—encouragement or caution—and illustrates these principles through examples from saints, personal mentors, and philosophical practice.

25. Anaxagoras, Mind as Mover, and the Common Ground of Change #

This lecture examines Anaxagoras’s concept of the Greater Mind (Νοῦς) as the mover of the universe, comparing it to Empedocles’s principles of love and hate. Berquist explores how Aristotle finds a common philosophical ground among disagreeing pre-Socratic philosophers by identifying that all understand change through contraries. The lecture demonstrates that this principle—whether expressed as condensation/rarefaction, mixture/segregation, or other contrary pairs—is not a freely imagined hypothesis but something forced upon the mind by truth itself, appearing universally across cultures and centuries.

26. Aristotle’s Method: Becoming Strong in Common Truth #

This lecture explores Aristotle’s strategy for responding to disagreement among natural philosophers by identifying what is common to all their accounts despite their particular differences. Berquist examines how all thinkers—ancient and modern, East and West—recognize that change involves contraries, arguing this principle is forced on the mind by truth itself rather than freely imagined. The lecture also distinguishes three fundamentally different kinds of beginnings: those in experimental science (hypotheses), philosophy (necessary truths), and theology (faith), showing how confusing these types leads to philosophical error.

27. Becoming Strong in Common Ground: Agreement Among Philosophers #

This lecture explores Aristotle’s method of ‘becoming strong’ by identifying what all pre-Socratic philosophers have in common despite their apparent disagreements. Berquist demonstrates how the principle of contraries (or opposites) is universally recognized as the basis of change, illustrating this through examples ranging from philosophy to science to everyday observation. The lecture emphasizes that this common principle is forced upon the mind by truth itself rather than freely imagined, and introduces the role of proportion and privation in understanding philosophical agreement.

28. Modern Physics, Mathematics, and the Problem of Knowledge #

This lecture examines the epistemological crisis in modern physics and experimental science, particularly how mathematical descriptions of nature contain neither matter nor motion, creating a fundamental problem for natural philosophy. Berquist contrasts Aristotelian natural philosophy—which seeks to understand the order in things themselves—with modern scientific methodology that claims to know only what it makes through experiment. He traces this problem from Kant’s philosophy of science through Marx and contemporary physicists like Heisenberg and Weizsäcker, ultimately arguing that confining human knowledge to what we make leads to a kind of intellectual solitary confinement.

29. The Third Principle: Resolving Contradiction in Change #

This lecture explores Aristotle’s argument for why two contraries alone are insufficient to explain change, requiring a third principle (the subject or substrate). Berquist emphasizes how the resolution of apparent contradictions—particularly the paradox that ’the hard becomes soft’—drives the development of human knowledge. The lecture demonstrates how distinguishing between a thing ‘as such’ and what happens to it ‘by accident’ resolves logical impossibilities and reveals the composite nature of changeable things.

30. Contradiction, Harmony, and the Discovery of Truth #

This lecture explores how contradiction functions as a driving force in the advancement of human knowledge across philosophy, science, and theology. Drawing on insights from Heraclitus, Plato, Aristotle, and modern physicists like Einstein and Bohr, Berquist demonstrates that apparent contradictions conceal hidden harmonies, and that the ability to recognize and resolve contradictions is essential to the discovery of truth. The lecture emphasizes Aristotle’s dialectical method and its application throughout the medieval scholastic tradition.

31. Contradiction as a Heuristic Tool Across Philosophy, Science, and Theology #

This lecture explores how contradiction functions as a fundamental tool for discovering truth across philosophy, science, and theology. Professor Berquist demonstrates that the human mind cannot accept contradiction, which forces it to seek resolution and deeper understanding. Through extensive readings from Aristotle, Heraclitus, Max Planck, Einstein, Niels Bohr, Jesus, Augustine, and Thomas Aquinas, the lecture shows that apparent contradictions in theory and experience consistently point toward more comprehensive and hidden harmonies that advance human knowledge.

32. The Three Principles of Change: Substance and Contraries #

Berquist examines Aristotle’s argument that change requires three principles: two contraries and an underlying subject. The lecture explores the apparent contradiction between arguing that contraries (accidents) are principles while substance must also be a principle, and resolves this through understanding Aristotle’s dialectical method. Key distinctions between substance and accident, and the principle of fewness are examined to explain why three principles are necessary and sufficient.

33. Dialectical Reasoning and the Three Principles of Change #

This lecture explores how Aristotle argues for three principles of change (two contraries and an underlying subject) while employing dialectical rather than demonstrative reasoning. Berquist examines the apparent contradiction in Aristotle’s arguments—reasoning from both ’there are contraries in substance’ and ’there are no contraries in substance’—resolving it through Thomas Aquinas’s insight that Aristotle proceeds from probable opinions. The lecture clarifies the distinction between contrary differences and contrary species, and explains why change is impossible without a third thing underlying the contraries.

34. The Principle of Three Across All Knowledge #

Berquist explores the principle that ’three is enough’ and often ‘all that is needed’ across multiple domains of human knowledge and experience. Beginning with Aristotle’s observation about three dimensions and the structure of change, he demonstrates how three emerges as a fundamental organizing principle in logic, rhetoric, grammar, poetry, music, natural science, and daily life. The lecture argues that this principle reflects something deep about the structure of reality and represents an optimal balance between necessity and sufficiency.

35. The Principle of Three in Physics and Theology #

Berquist explores the ubiquity and necessity of the number three across multiple domains: physics (Planck’s quantum of action, velocity of light, and atomic length as three universal constants), theology (the Trinity, Christ’s three offices, three theological virtues), and natural philosophy (beginning, middle, and end as the structure of perfection). He argues that three represents completeness in creatures and reflects the divine structure itself, drawing on Heisenberg’s physics and Thomas Aquinas’s metaphysics to show how three appears as both a mathematical necessity and a manifestation of divine perfection.

36. Mind, Nature, and the Stability of Concepts #

This lecture explores how the human mind’s capacity for understanding the universal demonstrates its unlimited nature, drawing on insights from modern physics about the stability of natural language concepts. Berquist examines how we know nature through its effects and operations, discusses the role of sensible qualities and motion in understanding natural things, and applies Aristotelian principles about what is better (ends vs. means) through both induction and formal logic, using examples from mathematics, Shakespeare, and contemporary physics.

37. The Three Things in Every Becoming #

This lecture examines Aristotle’s analysis of becoming (γένεσις/genesis) in Readings 12-13 of the Physics, establishing that every instance of becoming involves three essential elements: something that comes to be, something that remains, and something that is lost. Berquist demonstrates how universal human speech patterns reveal an implicit common understanding of this metaphysical structure, showing that the way all people speak about becoming—using two distinct names for the subject and consistently employing the preposition ‘from’ with what is lost—reflects genuine insight into the nature of change.

38. Causes in Becoming and Prime Matter #

This lecture explores Reading 13 of Aristotle’s Physics, examining how only two of the three components in becoming are true causes of what comes to be: matter and form, while the contrary plays no causal role. Berquist then moves to the most difficult aspect—prime matter—explaining how it is knowable only through proportion, why early Greek philosophers failed to understand it, and how modern physics struggles with similar conceptual difficulties regarding the nature of elementary particles.

39. Prime Matter, Potentiality, and Understanding Substantial Change #

This lecture explores the nature of prime matter as pure potentiality and its necessity for explaining substantial change. Berquist examines why prime matter is knowable only through proportion (like clay to shapes), discusses the fundamental difficulty the human mind has in understanding ability/potentiality, and demonstrates how pre-Socratic philosophers and modern scientists struggle with the same conceptual problem. The lecture culminates in examining how understanding the soul as a substantial form (rather than as mere harmony or as a complete substance apart from the body) resolves apparent contradictions in Plato’s Phaedo.

40. Aristotle’s Critique of Anaxagoras and the Principle of Fewness #

This lecture examines Aristotle’s eight arguments against Anaxagoras’s theory that everything is mixed in everything in infinite, infinitely small pieces. Berquist emphasizes how three of these arguments (1, 5, and 8) are grounded in the principle of fewness—that fewer causes are preferable to infinite ones if they sufficiently explain phenomena. The lecture connects this ancient critique to modern physics and shows how the confusion of actuality with potentiality underlies Anaxagoras’s error.

41. Aristotle’s Arguments Against Anaxagoras and the Second Difference in Quantity #

This lecture examines Aristotle’s refutation of Anaxagoras’s doctrine that everything is mixed in everything through a series of eight arguments. Berquist groups these arguments according to their philosophical principles: arguments 1, 5, and 8 rely on the principle of fewness and knowability (common to classical physics), while arguments 2, 3, and 4 expose the second difference between mathematical and natural quantity—the discovery that natural quantities have limits due to the natures of things, a principle that characterizes modern 20th-century physics. The lecture connects these ancient philosophical critiques to contemporary quantum theory and relativity.

42. Pantheism, Potentiality, and the Confusion of Matter with Privation #

This lecture explores how philosophical errors arise from confusing potentiality (ability) with actuality, using examples from pantheism, mathematics, and natural science. Berquist examines the common human difficulty in understanding potentiality and how thinkers like Anaxagoras and the Greeks conflated these concepts. The lecture culminates in previewing the crucial distinction between matter and lack of form (privation), setting up the fifteenth reading on becoming.

43. Matter, Form, and Privation: Distinguishing Three Principles of Change #

This lecture explores Aristotle’s critique of Plato’s confusion between matter and privation (lack of form), establishing that these must be distinguished as three separate principles in any account of change and becoming. Berquist demonstrates through logical argument and concrete examples that matter and privation relate differently to form, and that confusing them leads to the fallacy of the accidental—a mistake that has persisted through modern philosophy. The lecture establishes the metaphysical foundation for understanding why form is godlike, good, and desirable, while privation is fundamentally a non-being that cannot be the subject of desire.

44. Matter, Form, and the Fallacy of the Accidental #

This lecture examines Aristotle’s critique of Plato’s confusion between matter and lack of form, establishing the foundational distinction between these two principles. Berquist demonstrates how this confusion underlies the fallacy of the accidental—a logical error that deceives even the wise by treating necessarily present accidents as essential causes. The lecture traces this fallacy through multiple domains: teaching and ignorance, human freedom and indetermination (critiquing Sartre), the nature of evil as privation, and the structure of human acts. Throughout, Berquist emphasizes that understanding potentiality and actuality is essential for sound philosophy.

45. The Four Kinds of Causes and Their Univocal Meaning #

Berquist examines Aristotle’s distinction of the four kinds of causes (material, formal, efficient, and final), arguing that while each is a ‘cause’ in a different sense, they share a common notion of being responsible for the being or becoming of another. He demonstrates through linguistic and logical analysis how ‘cause’ is equivocal by reason rather than by chance, similar to how ‘part’ and ’thing’ have multiple but ordered meanings. The lecture establishes that this framework of causality is universally applicable to all sciences and philosophy.

46. Aristotle’s Four Kinds of Causes #

This lecture examines Aristotle’s doctrine of the four causes (material, formal, efficient, and final), establishing a common notion of causality while distinguishing how each kind operates differently. Berquist traces the historical development of these causes through pre-Socratic philosophy and demonstrates pedagogically how reason is forced to recognize the necessity of each kind of cause through concrete examples. The lecture emphasizes that these four causes exhaust the ways in which something can be responsible for the being or becoming of another.

47. The Four Kinds of Causes and Their Corollaries #

This lecture explores Aristotle’s doctrine of the four kinds of causes—material, formal, efficient, and final—demonstrating how reason is progressively forced to admit each through concrete examples like the word ‘cat’ and a wooden chair. Berquist explains three important corollaries: that multiple causes can affect the same thing, that two things can reciprocally cause each other in different senses, and that the same thing can be responsible for contrary effects. The lecture emphasizes the universal applicability of these causes across natural philosophy, mathematics, logic, and theology.

48. Generalizing the Four Causes and Their Divisions #

This lecture explores how Aristotle generalizes the four causes (material, formal, efficient, and final) beyond physical artifacts to abstract and immaterial domains, demonstrating their application in logic, definition, and theology. Berquist systematically examines multiple ways to divide the four causes into groups of two or one against three, showing how each division reveals different relationships between causes. The lecture culminates in an analysis of how God functions as a cause in only three senses (final, efficient, and exemplary) but never as material cause, establishing the fundamental importance of final causality to all philosophical understanding.

49. The Four Causes and Their Applications in Definition #

This lecture examines how the four causes (matter, form, efficient cause, and final cause) function within definitions of various things—from geometric theorems to sacraments to natural and social institutions. Berquist demonstrates through concrete examples that different kinds of things require different numbers and types of causes in their definitions, and that understanding which causes are relevant is essential to each science. He emphasizes that the final cause, though sometimes implicitly rather than explicitly present in definitions, has special importance because it is the cause of the other causes being causes.

50. Causes: Essential, Accidental, and the Problem of Chance #

This lecture explores Aristotle’s distinctions among types of causes, focusing on the division between essential causes (per se) and accidental causes (per accidens). Berquist explains two major kinds of accidental causation: luck and chance (causes of rare events arising from actions aimed at other ends) and the causa removens prohibens (removal of what prevents something). The lecture emphasizes why understanding these distinctions is crucial for natural philosophy and clarifies how accidental causes differ fundamentally from necessary causal chains.

51. Final Causality: Nature’s Purpose and Its Implications #

This lecture explores the fundamental question of whether nature acts for an end or purpose (final causality), establishing it as the causa causarum—the cause of causes. Berquist demonstrates why this question is essential not only for natural philosophy but for ethics, medicine, logic, and theology. The lecture addresses common misunderstandings about final causality, examines the overwhelming influence of custom over argument in modern thought, and identifies three major sources of modern culture’s rejection of teleology: the mercantile origin of modern cities, mathematical science and technology, and democratic revolutions.

52. Three Sources of Modern Anti-Teleological Custom #

Berquist examines three major historical sources that have shaped modern thought against the view that nature acts for an end: the mercantile origin of modern cities, the mathematization of natural science and mechanical arts, and democratic revolutions. He argues that these cultural forces, through custom, have made teleological thinking seem unscientific and irrational, despite being stronger influences than direct arguments against final causality.

53. Natural Teleology: Arguments For and Against Final Causality #

This lecture examines whether nature acts for an end or purpose (final causality). Berquist presents Aristotle’s six major arguments supporting teleology in nature—drawing on observations of spider webs, wasp behavior, bee navigation, and the organic structure of living bodies—and then addresses three principal counterarguments from modern thought: that action for an end requires mind which nature lacks, that nature produces defects contradicting purposiveness, and that mathematical chance and the principle of parsimony render final causality unnecessary. The lecture’s central concern is clarifying how action for an end can occur without conscious deliberation through the example of habit as ‘second nature.’

54. Nature Acting for an End: Three Major Objections and Replies #

Berquist examines three major philosophical objections to the claim that nature acts for an end (telos), offering detailed Thomistic replies to each. The lecture addresses whether action for an end requires a mind, whether nature’s production of defects disproves teleology, and whether the principle of parsimony makes the fourth cause (end) unnecessary. Throughout, Berquist demonstrates that mathematical chance cannot account for the consistent production of natural good and that the principle of simplicity itself presupposes nature’s purposive action.

55. Nature, Motion, and the Study of Natural Philosophy #

This lecture establishes why motion is central to understanding nature and why place, time, and the unlimited must be studied alongside it. Berquist examines Aristotle’s approach to natural philosophy as ’natural hearing’—learning from nature as a student learns from a teacher—and addresses modern objections (from Descartes and Locke) to defining motion, showing these objections rest on a confusion between certainty and clarity of understanding.

56. Defining Motion: Aristotle’s Definition and Modern Errors #

This lecture examines Aristotle’s definition of motion as ’the act of what is able to be, insofar as it is able to be,’ and critiques modern philosophers (Descartes and Locke) who claim motion cannot be defined. Berquist demonstrates that motion, while not simple to define, can be understood through the relationship between act and ability, and that motion is always ‘something of another’ (like health is of the body), providing the necessary multiplicity for definition.

57. Motion, Continuity, and Natural Philosophy #

This lecture explores why motion is central to understanding nature, examining the distinction between continuous and discrete quantities as defined in logic versus natural philosophy. Berquist demonstrates how motion’s continuous nature is infinitely divisible, contrasts this with discrete quantities like numbers, and shows how this distinction illuminates our understanding of reason, the soul, and knowledge itself.

58. Place, Time, and the Problem of Change #

This lecture explores Aristotle’s treatment of place, time, and the continuous as they relate to motion and change. Berquist addresses the classical paradox of becoming—the apparent contradiction that emerges when analyzing the transition from non-being to being—and shows how this problem plagued philosophers from the Middle Ages through Hegel and modern dialectics. The lecture demonstrates how understanding these concepts is essential for natural philosophy and connects to theological questions, particularly the problem of transubstantiation in eucharistic doctrine.

59. Definition of Motion and the Categories of Being #

Berquist explores Aristotle’s definition of motion as “the act of what is able to be as such,” examining why this definition requires three essential parts and how motion relates to the ten categories of being. The lecture addresses the problem of defining difficult philosophical concepts, the distinction between being and becoming, and why motion cannot be confused with other acts or static states.

60. Motion, Place, and the Eight Senses of ‘In’ #

This lecture continues Berquist’s exposition of Aristotle’s Physics, focusing on the definition of motion and introducing Aristotle’s treatment of place. The lecture emphasizes the three essential parts of motion’s definition (act, of what is able to be, as such), distinguishes motion from other acts through concrete examples, and begins an extended discussion of the eight senses of the word ‘in’ (ἐν) or ’to be in’, with particular attention to how understanding these senses prevents sophistic equivocation and grounds proper metaphysical understanding.

61. The Eight Senses of ‘In’ and Equivocation by Reason #

This lecture explores Aristotle’s and Thomas Aquinas’s analysis of the word ‘in’ as an equivocal term with eight related meanings ordered by reason. Berquist demonstrates how failure to distinguish these senses leads to logical fallacies and sophistic objections to fundamental axioms. The lecture emphasizes that understanding equivocal terms is essential for philosophy, particularly for defending axioms like ’nothing is in itself’ and for understanding proper categories in logic and metaphysics.

62. The Existence and Nature of Time #

This lecture investigates Aristotle’s inquiry into whether time truly exists, given that its parts (past and future) do not exist and the present moment (the now) has no duration. Berquist explores the paradoxes of the now, the relationship between time and motion, and the continuous divisibility of time through detailed analysis of Aristotle’s Physics Book IV. The lecture addresses Augustine’s famous confession about the difficulty of knowing what time is, and concludes that time exists, but only ‘barely and darkly.’

63. Time as the Number of Motion: Definition and Nature #

This lecture explores Aristotle’s investigation into the nature of time, focusing on why time is not motion itself but rather ‘something of motion.’ Berquist examines the relationship between time, motion, magnitude, and the now, introducing the classical definition of time as ’the number of motion according to before and after.’ The lecture addresses key paradoxes about the now’s existence and demonstrates how continuous magnitude entails the continuous and infinite divisibility of motion and time.

64. Time as the Number of Motion: Before and After #

This lecture explores Aristotle’s definition of time as the number of motion according to before and after, examining how time relates to magnitude, motion, and the now. Berquist analyzes the three senses of ‘before’ (temporal, ontological, and logical), demonstrates why before-and-after is first found in place/magnitude and then extends to motion and time, and works through the classical paradox of whether the now remains identical throughout time or is always different.

65. The Now and Time: Solving the Paradox Through Proportion #

This lecture resolves the classical paradox of the now—whether it is always the same or always different—through Aristotle’s method of proportion. Berquist explains how the now relates to time as the thing in motion relates to motion, allowing the now to be incorruptible in essence yet generative of time through its perpetual otherness in temporal position. The lecture emphasizes that understanding this proportion is essential to grasping how time itself is the number of motion’s before and after.

66. Time, Motion, and the Numbering Soul #

This lecture examines Aristotle’s definition of time as the number of motion according to before and after, with particular focus on why time barely exists without the numbering soul. Berquist explores what it means to be ‘in time’ (to be measured by time), discusses which motion should serve as the standard for measuring time, and addresses the paradox of time’s existence given that its components (before and after) never exist together. The lecture connects time to the development of reason in humans and animals, using examples ranging from infants learning temporal awareness to practical moral reasoning about pain and pleasure.

67. Boethius’s Definition of Eternity and Divine Knowledge #

This lecture explores Boethius’s classical definition of eternity as “the whole together and perfect possession of unending life” (tota simul et perfecta possessio vitae interminabilis) and its theological implications. Berquist analyzes each component of the definition—simul (together/at once), tota (whole), perfecta (perfect), possessio (possession), and interminabilis (unending)—to distinguish eternity from endless time and to illuminate how God knows all temporal events in His eternal now without violating human freedom. The lecture emphasizes that eternity involves a negation of both temporal succession (before and after) and temporal limits (beginning and end), and that possession in eternity means stable and complete holding of life, unlike the fleeting nature of temporal moments.

68. Eternity, Divine Knowledge, and the Philosophy of the Continuous #

This lecture explores the metaphysical distinction between time and eternity, God’s knowledge of future contingents, and the nature of continuity in natural philosophy. Berquist examines how God possesses life in an eternal now rather than a temporal succession, analyzes the sin of Adam and Eve as an attempt to gain knowledge of future contingents, and introduces the philosophical investigation of the continuous as more fundamental than geometry.

69. The Continuous: Definitions, Divisibility, and Becoming #

Berquist explores the fundamental nature of the continuous (τὸ συνεχές) as that whose parts meet at a common boundary, distinguishing it from the touching and the next. He examines why the continuous is foundational to human knowledge, language, and reasoning, and addresses classical paradoxes about becoming and change, particularly the problem of transition from non-being to being and Zeno’s paradoxes. The lecture establishes that understanding the continuous is essential for later proving the immateriality of reason and the immortality of the soul.

70. Reason, the Brain, and the Immateriality of the Soul #

This lecture explores the relationship between reason, the brain, and the immateriality of the soul through the lens of how continuous things are known in a non-continuous way. Berquist argues that understanding the universal in the form of a definition proves that reason itself is not a body, and therefore the soul’s existence is not entirely immersed in the body. He addresses common scientific arguments conflating the brain’s necessity for thought with the brain being the organ of thought, using the light bulb example to distinguish between interfering with an organ versus interfering with the object or conditions of knowledge.

71. The Continuous and the Problem of Indivisibles #

This lecture explores Aristotle’s foundational analysis of the continuous (τὸ συνεχές) and demonstrates why magnitudes cannot be composed of indivisibles. Berquist works through the definitions of continuous, touching (ἁπτόμενα), and next (ἐφεξῆς), then develops the central argument that lines cannot be composed of points, surfaces of lines, or bodies of surfaces. The lecture addresses Zeno’s paradoxes and shows how understanding the continuous is prerequisite for grasping immaterial realities in both philosophy and theology.

72. Reason, Causes, and the Perfection of Reasoning #

Berquist explores the nature of reason as a thought of why, distinguishing between weak reasons (authority, example) and perfect reasons that reveal the actual cause of why something must be so. Using geometric examples and practical illustrations, he demonstrates that the best reasons are those where the reason for thinking something is true coincides with the reason why it is true. The lecture emphasizes the importance of grasping causes rather than relying on mere opinion or experience, and includes extended discussion of how fiction and fictions—including those in science and history—can be useful while remaining fundamentally fictional.

73. The Continuous: Foundational to All Philosophy #

Berquist establishes the philosophy of the continuous as absolutely fundamental to all philosophical inquiry—from natural philosophy through mathematics to metaphysics and theology. The lecture demonstrates how the continuous is indispensable for understanding motion, time, place, geometry, number, and even immaterial substances like angels and God. He emphasizes why this inquiry belongs to natural philosophy rather than geometry, and shows how the continuous relates to basic philosophical concepts like being, unity, and causation.

74. The Continuous, Indivisibles, and the Axiom of Distinction #

This lecture explores Aristotle’s demonstration that the continuous cannot be composed of indivisibles (points), using definitions of the continuous, the nature of touching and boundaries, and fundamental axioms about distinction and limits. Berquist analyzes the logical structure of Aristotle’s argument, clarifies equivocations in key terms, and illustrates how axioms like ’the edge and that which it is an edge of are other’ underpin natural philosophy and metaphysics.

75. The Continuous: Composition, Divisibility, and Circular Reasoning #

This lecture explores Aristotle’s arguments against the composition of the continuous from indivisibles, examining the relationship between two definitions of the continuous and investigating apparent circular reasoning in their demonstration. Berquist demonstrates pedagogically why points cannot touch or compose a line, and discusses how the reasoning from the first definition (parts with common boundary) relates to the second definition (divisible forever), drawing parallels to similar issues in metaphysics and epistemology.

76. God’s Immutability and the Order of Divine Attributes #

This lecture examines why Thomas Aquinas orders the discussion of God’s attributes differently in the Summa Contra Gentiles compared to the Summa Theologiae, focusing particularly on how the more developed argument for the unmoved mover in the Contra Gentiles naturally leads to treating God’s immutability first. Berquist explores the relationship between proofs of God’s existence and the logical ordering of attributes, drawing parallels to geometric proofs in Euclid where theorems can be proven in alternative ways and used to demonstrate convertible properties.

77. Natural Understanding and the Axiom of Limits #

This lecture explores the axiom that nothing is an end or limit of itself, demonstrating how this self-evident truth is naturally known by reason. Berquist examines the four senses of ’end’ or ’limit’ in Aristotle’s metaphysics, illustrates how definitions function as limits that separate things from all others, and shows the complete dependence of philosophy upon natural understanding. The lecture addresses how modern philosophy’s rejection of natural knowledge leads to intellectual confusion and moral collapse.

78. Continuous Magnitude, Motion, and Time: Infinite Divisibility #

This lecture examines Aristotle’s demonstration that magnitude, motion, and time are continuous quantities that cannot be composed of indivisibles but must be infinitely divisible. Berquist uses the argument from faster and slower bodies to show how two naturally known truths about relative motion force us to conclude that both distance and time are divisible forever. He contrasts this with modern misunderstandings about composition from points and illustrates the relationship between natural philosophy and mathematics.

79. False Imagination, Natural Understanding, and the Examined Life #

This lecture explores the concept of false imagination as a primary source of deception in human knowing, examining how we mistakenly imagine things that cannot be imagined (like the soul) or imagine them differently than they are. Berquist connects this to natural understanding, the unexamined life, and the modern philosophical revolt from natural axioms, using examples from geometry, physics, and everyday experience to illustrate how proper understanding requires distinguishing between potency and actuality, and between apparent and real contradictions.

80. Scientific Hypothesis, Contradiction, and the Road to Knowledge #

This lecture explores the nature of scientific hypothesis as freely imagined and tested conjecture, examining famous examples like Dirac’s prediction of the positron and the history of Newtonian physics. Berquist discusses how apparent contradictions in sense experience (particularly through Parmenides, Heraclitus, and Zeno) point to hidden truths rather than genuine contradictions in reality, and argues that Aristotle’s solution reconciles the road from the senses with the principle of non-contradiction by recognizing the difference between accidental and essential change.

81. The Indivisibility of the Now and Motion #

This lecture explores Aristotle’s demonstration that the now (nunc) is indivisible and serves as the common limit of past and future time. Berquist examines the relationship between the continuous and the indivisible, presents the faster-and-slower argument against divisibility of the now, and explains why motion cannot occur in an indivisible instant. The lecture clarifies how the now is the limit of time rather than time itself, and introduces the paradoxical imperfection of motion’s being.

82. The Now, Motion, and Rest in Time #

This lecture explores Aristotle’s analysis of the now (nyn) as an indivisible limit between past and future, establishing that motion cannot occur within the now and that both motion and rest require time for their actualization. Berquist examines three arguments proving the absence of rest in the now, clarifies the distinction between privation and mere negation, and discusses how the imperfection of motion reveals its tenuous ontological status.

83. Motion, Divisibility, and the Nature of the Now #

This lecture explores Aristotle’s argument that whatever undergoes change must be divisible, using the examples of local motion and qualitative alteration. Berquist demonstrates why motion cannot occur in an indivisible instant (the now) and why this reveals the paradoxical minimal existence of motion itself. The lecture also touches on the philosophical difficulty of understanding time and motion, connecting classical arguments to modern physics and quantum theory.

84. The Divisibility of Motion and Time #

This lecture examines how motion is divisible in two fundamental ways: through the divisibility of the thing being moved and through the divisibility of time. Berquist analyzes Thomas Aquinas’s treatment of motion’s structure, demonstrating that the divisibility of the moving subject is foundational to understanding motion’s divisibility, and that time’s divisions necessarily correspond to motion’s divisions.

85. First in Change: The Indivisible Moment of Completion #

This lecture examines Aristotle’s demonstration that when change is completed, there is a first indivisible moment when the thing has changed and is in the term to which it has changed. Berquist analyzes change according to contradiction (from non-being to being) as the clearest case, then extends the argument to all types of change. He explores the meanings of ‘first’ and ‘before/after’ in relation to order and distinction, including an extended discussion of how these concepts apply to theological matters like the Trinity.

86. Motion, Continuity, and the Paradox of First #

This lecture examines Aristotle’s analysis of motion and change, focusing on the paradoxical structure of continuous motion. Berquist explores why there is a first indivisible moment when change is completed, yet no first distance traveled or first time of motion begins. The discussion centers on the relationship between the continuous nature of motion and the impossibility of identifying discrete beginnings, with application to proving the existence of an unmoved mover.

87. Order, Symmetry, and the Problem of First in Motion #

This lecture explores the distinction between order (understood strictly as before-and-after) and symmetry in various contexts, including the Trinity, literature, and art. The bulk of the lecture addresses Aristotle’s solution to the paradox of becoming: how something can change from not-being-A to being-A without both being and not-being A in the same instant. Berquist explains that there is no first instant when motion begins (due to infinite divisibility of time), but there is a first instant when motion is completed (which is indivisible), and demonstrates how this principle resolves both the logical paradox and the theological problem of transubstantiation.

88. Motion, Time, and the Now: Resolving Zeno’s Paradoxes #

This lecture examines the fundamental problems Zeno’s paradoxes pose for understanding motion and time, with particular attention to the relationship between the indivisible now and motion. Berquist explores Aristotle’s solution through the distinction between potential and actual division, and discusses how modern science employs idealizations that depart from reality. The lecture emphasizes the difficulty of understanding motion and time despite daily experience with them.

89. Zeno’s Paradoxes and the Problem of Motion #

This lecture examines Zeno’s arguments against motion as presented in Aristotle’s Physics Book 6. Berquist analyzes six of Zeno’s paradoxes—the Dichotomy, Achilles and the Tortoise, the Arrow, the Stadium, change between contradictories, and circular motion—explaining how Aristotle resolves them through proper understanding of the continuous, divisibility, potency versus actuality, and the nature of time. The lecture emphasizes the philosophical danger of confusing potential division with actual division, and connects Zeno’s ancient problems to modern physics.

90. Wisdom, Slowness, and the Avoidance of Intellectual Stumbling #

This lecture explores the intimate connection between wisdom and slowness, arguing that true wisdom is characterized not by hastiness but by careful, deliberate consideration—what Berquist calls sapida scientia (savory knowledge). The lecture identifies seven distinct contexts in which the wise person necessarily proceeds slowly to avoid the stumbling that afflicts hasty thinkers, examining how modern philosophy has departed from this wisdom by rejecting wonder, attacking the natural road of knowledge, and dismissing foundational axioms.

91. Seven Places Where the Wise Proceed Slowly #

Berquist examines wisdom as deliberate slowness through seven contexts where careful consideration is essential: when many things must be considered, when something is difficult to know, when small beginnings have great power, when knowledge follows a road, when moving from general to particular knowledge, when encountering equivocal words, and when reading wise authors. The lecture emphasizes that wisdom (sapida scientia) is not hesitation but savory knowledge worth lingering over, and explores how modern philosophy has stumbled by revolting against natural principles of knowledge.

92. Equivocal Words and the Nature of Badness #

This lecture explores the distinction between equivocal by reason and equivocal by chance, using the word ‘bad’ as the primary example of an equivocal by reason term. Berquist demonstrates that ‘bad’ has three interconnected meanings—lack, what has the lack, and what causes the lack—all of which must be understood in relation to nature. The fundamental principle developed is that nature (what a thing is) is the measure of what is good or bad for that thing.

93. God’s Existence and the Fool: Philosophy’s Foundation #

Berquist examines Thomas Aquinas’s argument that denying God’s existence is foolish, drawing from Scripture and Greek philosophy to show that true philosophy presupposes belief in God. He discusses how humility before divine wisdom is essential to the philosophical enterprise, and introduces the structure of Aquinas’s demonstrations of God’s existence in the Summa Contra Gentiles, particularly the argument from motion, while comparing its treatment with the Summa Theologiae.

94. The First Way: Motion and the Unmoved Mover #

Berquist analyzes Aquinas’s treatment of Aristotle’s first argument for God’s existence from motion. The lecture examines the two key premises that ground the argument: (1) everything in motion is moved by another, and (2) an infinite regress of movers is impossible. Through careful logical analysis and reference to Aristotle’s Physics, Berquist demonstrates how Thomas proves these premises and why the conclusion necessarily points to an unmoved mover as God.

95. The Second Way: Per Se and Per Accidens in Motion #

This lecture explores the second argument for God’s existence from Thomas Aquinas, focusing on the distinction between per se (through itself) and per accidens (by accident) truth. Berquist examines how this distinction applies to the statement ’every mover is moved’ and why an infinite regress of movers is impossible. The lecture also includes extended discussion of the middle mover argument illustrated through concrete examples (trains, chandeliers) and clarifies key logical and philosophical terminology.

96. Categories, Predicaments, and the Etymology of Philosophical Language #

This lecture explores the etymology and philosophical significance of key terms—particularly ‘category’ (from Greek categoria, meaning accusation in a courtroom) and ‘predicament’ (from Latin predicamentum, meaning a situation or set-up). Berquist examines how abstract philosophical concepts have influenced everyday speech, traces the origin of these terms to legal contexts, and discusses how understanding etymology illuminates the ten Aristotelian categories as the ’ten supreme accusations’ or highest genera into which all being is divided.

97. Aristotle’s Arguments for the Unmoved Mover #

This lecture explores Aristotle’s arguments for an unmoved mover, focusing on the problem of infinite regress in movers, the nature of self-moving things, and the requirement for an eternal cause of perpetual generation. Berquist emphasizes how corruptible, self-moving creatures (animals) cannot account for the eternity of motion and must be reduced to an eternal, immobile first mover. The lecture concludes by examining how the desirable (as object of appetite) functions as an unmoved mover, leading toward Thomas’s identification of this with God.