45. Accidental and Substantial Form: The Proportion

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Lecture Notes

Main Topics #

The Analogy of Clay and Shapes #

• Clay is able to be sphere, cube, or pyramid, but not simultaneously
• Clay itself does not become a sphere; something else makes the clay actually spherical
• This shape (accidental form) is proportional to the substantial form that makes matter actually a man or lion
• The proportion reveals the nature of underlying potentiality without requiring direct knowledge of first matter

Accidental Forms in Aristotle’s Account #

• Aristotle catalogues multiple types of accidental differences:
  • Mode of composition: Water as H₂O (ratio); Manhattan as whiskey and vermouth in specific proportion
  • Being bound together: Bundle (like bound hair)
  • Being glued together: Book
  • Being nailed or screwed together: Wooden box
  • Position: Threshold (below) vs. lintel (above); dinner vs. breakfast (temporal position)
  • Sensible qualities: Hardness/softness, density/rareness, dryness/wetness
• Despite their variety, accidental forms are responsible for a thing being what it is in a qualified way
• A chair is a chair more because of its shape than because of its matter (wood in potentiality)

The Nature of Substantial Form #

• Substantial form stands in proportion to accidental form, as accidental form to matter
• By accidental form, something is in a qualified sense (e.g., I am a geometer)
• By substantial form, something is simply, without qualification (e.g., I am)
• When substantial form is lost, the thing ceases to be entirely
• When accidental form is lost, the thing ceases to be in some respect only

Differences Between Accidental and Substantial Form #

Regarding the Subject:

• Accidental form comes to a subject that is already an actual substance
• Substantial form comes to a subject that exists only in potentiality (first matter)

Regarding Actuality:

• In accidental form, actuality is found first in the subject before it is in the form itself
• In substantial form, actuality is found first in the form, not in its subject (which is pure potentiality)

Regarding Being:

• Accidental form: Something “is” in a qualified way (secundum quid)
• Substantial form: Something “is” simply and without qualification (simpliciter)

Examples of Difference:

• When I study Euclid, I come to be—a geometer (qualified being)
• When I die, I cease to be (unqualified cessation of being)
• Losing geometry: I cease to be a geometer (but I still am)
• Losing substantial form (death): I cease to be entirely

Likenesses Between Forms #

• Both accidental and substantial form are acts as opposed to abilities
• Through both forms, something is said to be in some way
• The relationship reveals proportional likeness (requiring greater intellectual effort than simple likeness)

Key Arguments #

The Problem of Multiple Accidental Differences #

• Aristotle shows that things can differ by composition, binding, position, quality, and other modes
• Yet all these differences pale before the fundamental question: What makes something actually a substance rather than merely potentially one?
• Accidental forms multiply, but their very plurality points to the need for something more fundamental: substantial form

The Inadequacy of Matter Alone #

• Clay is only able to be a sphere; clay as such is not a sphere
• Similarly, first matter is only able to be a man; first matter alone does not make anything actually be
• Something beyond the subject is required to actualize potentiality

Why Substantial Form is Primary Substance #

• Accidental forms depend on a subject already existing in actuality
• Substantial form does not depend on a pre-existing actual subject; it actualizes pure potentiality
• Therefore, substantial form has a priority and causality that accidental form lacks

Important Definitions #

Accidental Form (forma accidentalis) #

• A form that comes to a subject already existing as an actual substance
• Responsible for a thing being in a qualified or secondary way (secundum quid)
• Can be lost without the thing ceasing to exist
• Examples: whiteness, hardness, geometry (as knowledge), position

Substantial Form (forma substantialis) #

• A form that actualizes matter in potentiality
• Responsible for a thing being simply and without qualification (simpliciter)
• Loss of substantial form means the thing ceases to be entirely
• Makes a thing the kind of thing it is (man, lion, oak, etc.)

First Matter (materia prima) #

• The ultimate underlying subject of all material change
• Exists in pure potentiality; never found in isolation in nature
• Knowable only through proportion (by analogy with how clay relates to shapes)
• That which is common to all substances undergoing substantial change

Potentiality (potentia) vs. Actuality (actus) #

• Clay is in potentiality to be shaped; the shape is actuality
• First matter is in potentiality to be any substance; substantial form is actuality
• Actuality always precedes potentiality ontologically

Examples & Illustrations #

The Clay and Shapes #

• Clay can become sphere, cube, or pyramid
• Clay is not sphere by being clay; some form makes it actually spherical
• When clay becomes a cube, it ceases to be a sphere (formal change without substantial change)
• The relation parallels first matter to substantial forms

Composition by Ratio #

• Manhattan: Whiskey and sweet vermouth in 2:1 ratio
• Stinger: Brandy and white crème de menthe in 2:1 ratio (Berquist corrects: “I’ve been doing a bad thing”)
• Same formal ratio, different matter; shows that form alone does not determine what something is

The Threshold and Lintel #

• Same material (wood) but different positioning
• Threshold: positioned below; Lintel: positioned above
• Position (a form) is what makes them different, not matter
• Illustrates how accidental form determines what something is called

Temporal Position #

• Dinner vs. breakfast: Same food, different times
• Time is a kind of position that makes the difference in what we call it
• Neither requires material difference; form (temporal order) creates the distinction

Being and Ceasing to Be #

• Student leaving classroom: “You will cease to be” (sounds like threat)
• Proper meaning: “You will cease to be in the room” (qualified cessation)
• Entering classroom: “You came to be in the room” (qualified generation)
• Dying: “I cease to be” (unqualified cessation of being entirely)

The Carpenter and the Chair #

• Carpenter makes the chair (the composite of matter and form)
• Carpenter does not make the form (shape) itself as such
• The form comes into being only accidentally through the generation of the composite
• Shows form is not generated in the same way matter is shaped

Names and Diminutives #

• Ann vs. Annette: Annette means “little Ann”
• Dad vs. Daddy: Daddy is the childish diminutive
• Just as suffixes diminish or modify names, qualifications modify the sense of “being”
• Illustrates how language marks the difference between simple and qualified being

Questions Addressed #

How can we understand first matter if it’s pure potentiality? #

• Answer: Through proportion. Just as we understand how clay relates to shapes without studying clay itself in isolation, we understand first matter through its proportion to actual substances (man, lion, stone)
• We infer first matter from the fact that one substance can become another while something persists

What is the relationship between accidental and substantial form? #

• Answer: Accidental form is to the actual substance what substantial form is to first matter. Both are acts that determine a subject, but substantial form actualizes pure potentiality while accidental form modifies what is already actual

If accidental forms differ so vastly (composition, position, quality, etc.), how can we speak of them together? #

• Answer: They all share the character of being forms that determine a subject that is already actual. They make something be in a secondary or qualified way, not in the simple, unqualified way that substantial form does

How do we know that substantial form is more real than accidental form? #

• Answer: Because actuality is found first in substantial form (not in its subject), whereas in accidental form, actuality is already found in the subject. What actualizes pure potentiality is more fundamental than what modifies what is already actual

Theological and Philosophical Extensions #

Immaterial Substances (Angels) #

• Angels are pure form without matter
• Being form without matter makes them more substantial, more real than composite beings
• Each angel is unique in its form (no matter-quantity basis for multiplicity)
• Berquist: “They’re more real than you are”

The Resurrection of the Body #

• Mary’s assumption: If the body of Mary is not assumed into heaven, then Mary (as the composite of soul and body) is not fully in heaven
• Human being is properly soul-body composite; the soul alone is not the whole person
• Strictly speaking, “St. Peter is in heaven” is synecdoche; the soul of Peter is in heaven
• After the last judgment, humans will recover their bodies and be fully present in heaven

Additional Context #

Aristotle on the Heavens #

• Aristotle believed celestial bodies (sun, moon, stars) do not undergo substantial change or alteration
• He noted their inaccessibility: unlike animals (which can be dissected), heavenly bodies cannot be examined
• Thomas Aquinas acknowledges Aristotle’s limitation here; substantial changes in heavenly bodies may take longer than human lifespans to observe
• Modern science has revealed more about celestial change than Aristotle could know

Etymology: Nature (natura) vs. Substance (substantia) #

• Natura comes from natus (birth), originally meaning generation
• Extended to mean the source of change within a thing
• Substantia means “standing under” (sub-stare), the underlying subject
• These words have overlapping but distinct meanings; sometimes one meaning of nature coincides with one meaning of substance

The Order of Knowing vs. Order of Being #

• Matter is known to be substance before form is known to be substance
• Yet form is more substance (more real) than matter
• Nature is first known as matter (source of change), then understood as form
• Yet form is more nature than matter
• This inversion—reversed order of knowing and being—marks a key philosophical subtlety