26. Quality, Modus, and the Four Species of Determination

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Lecture Notes

Main Topics #

Thomas Aquinas on Modus and Quality’s Determination #

• Thomas uses modus (mode) and determinatio (determination) as synonyms when distinguishing the four species of quality
• Quality determines a subject in three distinct ways:
  1. According to nature itself (First Species: Habit and Disposition) — relates to good/bad disposition
  2. According to action and passion (Second and Third Species: Ability and Undergoing Qualities) — relates to easy/difficult, quick/slow, lasting/transient
  3. According to quantity (Fourth Species: Figure and Form) — without motion, without the notion of good/bad

The Problem: Why Use Modus for Quality? #

• Modus typically means measure — associated with quantity’s division and limitation
• Species of quantity are distinguished by measure — discrete and continuous are measured differently
• Question: Why should Thomas use modus to distinguish species of quality if quantity is what gets measured?

The Resolution: Modus as Limit/Boundary #

• Modus can also signify boundary or limit
• To be measurable, a quantity must also be limited
• Quality operates as a mode or way of limiting/determining a subject
• This sense aligns with how the word ‘modus’ means ‘way’ — modus predicandi (way of predicating), etc.

The Four Species and Their Modes of Determination #

First Species (Habit/Disposition)

• Determines subject according to nature and the end (what the nature is ordered to)
• Bears the notion of good or bad — you are well or ill-disposed toward your nature
• Can be easily or difficultly moved
• Example: A man with courage disposes him well toward danger; cowardice disposes him ill

Second and Third Species (Ability and Undergoing Quality)

• Determine subject according to action and passion — the principles of action/suffering
• These principles (matter and form) follow from nature
• Bear the notion of good or bad — something is done easily or difficultly, quickly or slowly, lastingly or transiently
• Relate to motion and change

Fourth Species (Figure/Form)

• Determines subject according to quantity alone
• Does not pertain to notions of good/bad (bene/male)
• Does not pertain to quickly or slowly changing (cito vel tarde transiens)
• Example: A square number (64) determined by its quantity, not by motion or value

Why Habit is First Among the Species #

• Though natural ability is more fundamental ontologically, habit is listed first
• Reason: Nature is first considered in a thing
• Habit’s determination relates directly to the end and nature of the thing
• The path to happiness is virtue (habit well-disposed); the path to misery is vice (habit ill-disposed)
• Therefore, what most directly affects human flourishing (good/bad disposition toward nature) is appropriately listed first

Measurability and Immeasurability #

• To be measurable, something must be limited (have boundaries)
• The infinite is described as immeasurable — it has no measure because it has no limit
• Shakespeare uses ‘immeasurable’ and ‘infinite’ almost synonymously in Timon of Athens: “Common mother thou whose womb immeasurable and infinite breast teams and feeds all”
• The Fourth Lateran Council uses immense (immensely) to describe God’s infinity — meaning unlimited
• Connection: Modus as limitation explains why quality (which limits/determines a subject) can be called a mode even though measure typically belongs to quantity

Key Arguments #

Why Thomas Uses Modus for Quality Despite Its Association with Quantity #

• Apparent Problem: Modus means measure; species of quantity are distinguished by measure; therefore modus seems inappropriate for quality
• Solution: Modus has multiple senses:
  • Modus as “measure” (primary sense for quantity)
  • Modus as “way” or “manner” (how something is done)
  • Modus as “limit” or “boundary” (how something is bounded/determined)
• All four species of quality determine or limit the subject in specific ways
• Therefore, modus (as limit/boundary) appropriately describes quality’s operation

The Connection Between Limitation and Measurability #

• What is measurable must have limits/boundaries (otherwise infinite, immeasurable)
• Quality limits or determines the subject according to different principles
• Therefore, quality can be said to operate as a modus (limit/determination)
• This explains why determinatio and modus are used synonymously in Thomas’s treatment

Important Definitions #

• Modus: Mode, way, manner, measure, boundary, or limit — used to describe how quality determines a subject
• Determinatio: Determination; the limiting of a subject according to different principles (nature, action/passion, quantity)
• Dispositio (bene/male): Being well or ill-disposed toward one’s nature
• Immensum (Immense): Used by the Fourth Lateran Council to describe God’s infinity — literally “not measured,” unlimited
• Cito/Tarde: Quickly/slowly — describing how action/passion occur

Examples & Illustrations #

Shakespeare on Measurable/Immeasurable #

• Timon of Athens: “Common mother thou whose womb immeasurable and infinite breast teams and feeds all”
• The womb’s room is described as both immeasurable and infinite — nearly synonymous terms
• Both convey the sense of having no limit, no boundary, no measure

Square Numbers and the Fourth Species #

• 64 is both a square number (8 × 8) and a cube number (4 × 4 × 4)
• These numbers are determined by their quantity and form, not by motion or good/bad
• The fourth species of quality determines by quantity alone, without the notion of motion or value
• The $64 question: cultural reference to 64 being a special number (both square and cube)

The Difference Between “How Much” and “How” #

• When asked about height on a driver’s license: “How tall are you?” → Answer: “Five foot eight” (quantity)
• When asked “How are you today?” → Answer: “I’m sick,” “I’m angry,” “I’m depressed” (quality)
• The word “how” (qualis in Latin) signifies the quality or determination of a thing, not its quantity
• This linguistic distinction reflects the metaphysical difference between how much (quantity) and how (quality)

Questions Addressed #

Why should Thomas use modus to distinguish quality when modus means measure and measure belongs to quantity? #

• Resolution: Modus has multiple senses beyond “measure” — it can mean “way,” “manner,” “limit,” or “boundary”
• Quality operates as a limit or determination of the subject according to different principles
• Therefore, modus (in the sense of “limit/boundary”) appropriately describes quality’s function
• This is why determinatio and modus are used synonymously

How does the fourth species of quality differ from the first three? #

• First three species: Determine subject according to nature, action/passion; relate to good/bad; admit motion
• Fourth species: Determines subject according to quantity alone; does not admit notions of good/bad; does not involve motion
• Example: A geometric shape (figure) is determined purely by its form/quantity; a virtue (habit) is determined by its relation to good/bad and to human nature’s end

What does it mean for something to be “immeasurable” or “infinite”? #

• The immeasurable is that which has no measure because it has no limit
• Shakespeare’s use in Timon of Athens: “immeasurable womb” and “infinite breast” convey the same idea — unlimited, unbounded
• The Fourth Lateran Council’s use of immense (immensely) for God follows the same logic — God is unlimited, beyond all measure
• This concept clarifies why modus (as limit) is essential to understanding quality: quality limits the subject, whereas infinity/immeasurability is the absence of such limitation