Aristotle: Metaphysics, Physics, & Psychology


Doctrines & Discoveries

Notes & Quotes



Plato: human: a featherless biped.

Stu Dent: behold a plucked chicken.

Forms are immanent real essences not transcendent Ideals {3.4}

Invented the science of logic virtually ex nihilo. {2}

Less interested in mathematics than Plato -- the arch rationalist

More interested in observation -- arch empiricist

perception provides bases for generalizations

 which, if true, amount to scientific knowledge of the world

penetrating even to the real essences of things

Affirmed reality & knowability of the material world and change

A brilliant scientist: founded the science of biology

systematic typological classification of organisms by genus (e.g., homo), and species(e.g., sapiens)

There's natural purposiveness in things; this provides objective bases for value judgments.

1.        “All men by nature desire to know.”

2.        "It must be held to be impossible that the substance, and that of which it is the substance, should exist apart; how, therefore, can the Ideas, being the substance of things, exist apart?"

3.        “And to say that [the Forms] are patterns, and the other things share in them is to use empty words and poetical metaphors."

4.        “[Forms] help in no wise towards the knowledge of the other things (or they are not even the substance of these, else they would have been in them.”

Ontology: Substance, Form, and Matter


BR: Bare matter is conceived as a potentiality of form; all [natural?] change is what we should call "evolution" in the sense that after the change the thing in question has more form than before.  That which has more form is . . . more "actual." 

The basic things -- what's really real -- are the many: particular things; primary substances e.g., Socrates, Bucephelus {2}

A primary substances are  this-somewhats: e.g., this brick; Socrates {4}

a form or essence: determining the what-ness: shape, etc. {1}

in some matter: the this-ness: so much clay; flesh, blood, etc.

Categories, essence, & accident {3}

relativity of matter

 flesh, blood, etc. are formed of earth air, etc.

prime matter distinguishable in thought only but incapable of independent (unformed) existence: c.f. Anaximander's aperion & Plato's "receptacle of becoming."

Aristotelian Forms

distinguishable in thought only -- not distinct in fact -- from the substances they inform

scientific forms may be captured by definitions -- especially functional definitions

Form follows function

knives are designed to cut

eyes are designed to see

Entelechy: Organic Forms or Natures are Dynamisms in things

Potentiality (material empowerment) & Actuality (formal development)

degrees of potentiality: flesh has more potentiality for humanization than earth; acorn is quite potentially an oak

1st  degree of actuality = capacity or ability

 2nd degree of actuality = exercise of the capacity or ability

1.        "By the term `universal' I mean that which is of such a nature as to be predicated of many subjects, by `individual' that which is not thus predicated."

2.        "It seems impossible that any universal term should be the name of a substance.  For ... the substance of each thing is that which is peculiar to it, which does not belong to anything else; but the universal is common, since that is called universal which is such as to belong to more than one thing.”

3.        “Terms which are in no way composite signify substance, quantity, quality, relation, place, time, position, state, action, or affection.” “Substance, in the truest and primary and most definite sense of the word, is that which is neither predicable in a subject nor present in a subject; for instance the individual man or horse.”

4.        “Everything but primary substances is either predicable of primary substance or present in a primary substance.”


received problem: how can something do both -- alter and remain the same -- at once


inorganic processes: different potentialities become activated or actualized in one & the same matter

organic processes: one and the same entelechy -- e.g., a living human organism, a human life -- expresses various natural capacities and undergoes various accidents

1.        [Natural things] present a feature in which they differ from other things which are not constituted by nature.  Each of them has within itself a principle of motion and of stationariness (in respect of place), or of growth and decrease, or by way of alteration."


Four Causes

4 Then there is what is a cause insofar as it is an end (telos): this is the purpose of a thing; in this sense, health, for instance, is the cause of a man's going for a walk.

Material cause: from what {1}

bricks, timbers, nails, etc.;

flesh, blood, bone, etc.

efficient cause = by what process {2}

carpentry, bricklaying, etc.

conception, growth, etc.

formal cause = according to what design {3}

what the blueprint expresses

what the correct scientific definition would express

final cause = for what purpose {4}: provide lodging: self-actualize


1.        In one sense, what is described as a cause is that material out of which a thing comes into being and which remains present in it. Such, for instance, is bronze in the case of a statue …

2.        In another sense, the form and pattern are a cause, that is to say the statement of the essenc­e … such, for instance, in the case of the octave, are the ratio of two to one ….

3.        Then there is the initiating source of change or rest: the person who advises an action, for instance, is a cause of the action; the father is the cause of his child; and in general, what produces is the cause of what is changed.

Function Transcends Form

Inherent function looks beyond the individual in reproduction

Ecologically: each a part of the universal one

All specific purposing (after apparent goods) obscurely strives toward the true Good; all want to imitate God as closely as possible.

1.        "[F]or any living thing . . .the most natural act is the production of another like itself ... in order that, so far as its nature allows, it may partake in the eternal and divine.”

The Prime Mover (aka God) & Big Cosmological Picture


BR: God is pure form and pure Actuality; in Him, therefore, there can be no change.



Pure Form/Actuality: The Transcendent One

Transcendent (Platonic) not immanent

An individual, not a kind?  No many of which it is the Type; so no resemblance/imitation problem. 

Unmoved Mover The big picture.  {4} {5}

Unmoved: yet actively self-contemplative!? {2} {3}

Mover: "moves as the object of desire does." {1}

"The good is that at which all things aim."

albeit obscurely (compare "imitation")

each according to its appearance to them

Compare: Plato's form of the Good

The big picture: cosmology & typology

the 5* spheres: stellar, planetary*, solar, lunar, sublunary

aether aka quintessence (a sort of spiritual material)

material: earth, air, fire, & water

Substance {6}

Immovable: God


Inalterable (& Imperishable): Heavenly Bodies: circular motion

Alterable (& Perishable): Physical Bodies

Unnatural: nonliving things; rocks, chairs, etc.

Natural: living things

insensible (& immobile): plants

sensible (& mobile): animals

irrational: brutes

rational: humans

1.        "There is something which moves without being moved, being eternal substance, and actuality.  And the object of desire and the object of thought move in this way; they move without being moved."

2.        "Now if you take away from a living being action, and still more production, what is left but contemplation?  Therefore the activity of God, which surpasses all others in blessedness, must be contemplative."

3.        "It must be of itself that the divine thought thinks (since it is the most excellent of things) and its thinking is a thinking on thinking."

4.        "[T]he final causes cannot go on ad infinitum -- walking being for the sake of health, this for the sake of happiness, happiness for the sake of something else, and so one thing always for the sake of another."

5.        "[T]here must necessarily be some . . . thing which, while it has the capacity of moving something else, is itself unmoved and exempt from all change."

6.        "Among substances are by general consent reckoned bodies and especially natural bodies; for they are the principles of all other bodies."

Psyche aka Soul

BR: “The soul, we are told, is the form of the body.  Here it is clear that "form" does not mean ‘shape’’… in Aristotle's system, the soul is what makes the body one thing. “(165)




The form of a living body.

Form is the principle of continuity of each substance {2}

In living bodies the principle of continuity is psyche -- an inherent principle of change & motion -- or soul.  {1}

The unity of an animal is the unity of a certain sort growth-maintenance-reproductive process --a life.

Definition: 1st grade of actuality of a natural organized body. {5}

1st grade = possession of  capacity (e.g., for thought when asleep)

2nd grade = exercise of the capacity (e.g., thinking when awake)

The three [types or levels] of psyche & their distinctive powers & functions: each is proximate matter for the next {4}

vegetative soul: life: nutrition (growth) & reproduction

animal soul: locomotion & sensation: ". . . nothing in vain."

human soul: rational thought

Sensation:  receiving the sensible forms of things without the matter

five senses (vision, hearing, taste, touch, smell) each have their special objects (color, sound, flavor, feels, odors) they unerringly detect. {3{

common sensibles (movement, rest, figure, magnitude) are not peculiar to any one sense but common to several or all.

1.        "Of natural bodies some have life in them, others not; by life we mean self-nutrition and growth (with its correlative decay).”

2.        "[W]e can dismiss as unnecessary the question whether the soul and the body are one: it is as meaningless as to ask whether the wax and the shape given to it by the stamp are one, or generally the matter of a thing and that of which it is the matter."

3.        "Each sense has one kind of object which it discerns, and never errs in reporting that what is before it is color or sound (though it may err as to what it is that is colored or where that is, or what it is that is sounding, or where that is."

4.        "The sentient faculty never exists without the nutritive, but the nutritive may exist without the sentient, as in the case of plants."

5.        “[T]he soul is the first grade of actuality of a natural body having life potentially in it.  The body so described is a body which is organized.”