Wednesday, May 12, 2010

Notes on the Philosophy of Aquinas

St. Thomas Aquinas, pray for us poor sinners!

1. The kinds, principles and causes of physical change
Important Texts: St. Thomas Aquinas, "On the Principles of Nature"
Important Notes: Definitions from "On the Principles of Nature"

Change: Transition
From (Terminus a quo) being to (terminus ad quem) non-being or vv. (coming-to-be, ceasing-to-be)

Supernatural changes:
Creation: nothing → something
Annihilation: something → nothing

Natural changes (something that is potentially F → something that is actually F):

Substantial (for x to be F is for X to be) – substantial predicates signify the substantial form
Accidental – For X to be F is for x to be Somehow (to be with quality; esse secundum quid)

It is form that becomes actual or ceases to be actual, and matter that is the underlying subject that remains the same throughout the change

substantial change requires prime matter as its underlying subject – prime matter characterizable as the only permanent subject of substantial change, that is receptive (potentially) of all natural material forms

Form & matter are two necessary principles of change
lack of form (privation) is a principle of change – not a positive entity, but a being of reason -- privation a necessary condition of physical change (in and of itself it is not effective=does not have intrinsic causal role; a condition of change but not responsible for sustaining being of either change or the terminus of the change)

external cause that brings form into actuality → the efficient cause – provides the energy for the coming-to-be of the form, which may coincidentally entail the ceasing-to-be of another form (e.g., heating paper to generate substantial form of fire out of prime matter of the paper – destruction of the sheet of paper)
Privation (principle but not a cause of change, since it is not a being), form, matter, efficient cause, and final cause (four causes)

Something can be a cause of itself in some respect and an effect in another respect at the same time. I can be a mover of myself, but not a per se cause of myself in the same respect. Nothing can be a per se cause of itself. God is not a self-caused cause, but an uncaused cause. He needs nothing to sustain His being/activity. On account of His simplicity He is not even a self-sustaining cause, but is in no need of sustenance.

Important Notes: "Per se vs. per accidens as they apply to privation"

2. Aquinas on being per accidens
Being with regard to accidental form

3. Aquinas's distinction of real beings vs. beings of reason

Important Notes: Yale Lecture on Being and Essence

There is only a distinction of reason between Socrates's animality and Socrates's humanity.

4. Materiality and metaphysical composition according to Aquinas -
Important Notes: "The types of composition in creatures distinguished by Aquinas"
Important Notes: "MAN=BODY+SOUL: Aquinas's Arithmetic of Human Nature"

5. Aquinas' thesis of the unity of substantial forms and its consequences in his philosophical anthropologyYale Lecture on Being and Essence, footnote in textbook that gives us outline of main argument for Aquinas's thesis of unity of substantial forms

Only one substantial form informing one substance. Two distinct acts of being would have to be one and the same thing which they inform, which is impossible.

There is just one substantial form of the human body; the cadaver is a new body with a new substantial form; what remains is only the prime matter that used to be informed by a soul and is now informed by the form of a cadaver. No accidental quality (shape, color) that cadaver seems to share with form of living body is numerically the same, since the living body is not the same body as the cadaver.

6. Individuation and materiality according to Aquinas
Individuation of our souls in afterlife (before Resurrection) is not due to actual inherence in matter, but in past inherence in matter which individuated them in the first place

1. suppositum (subsistent entity) has this act of being (esse) as quod est (as that which is)
2. The form has esse as quo est (as that by which the thing exists)
3. Matter has esse as in quo est (as its subject)

Averroes: if the intellect is immaterial, then it cannot be multiplied with the multiplication of bodies.
Avicenna: if human souls are individuated in their bodies, they can continue to be individuated after their separation from their bodies.

All human souls belong to the same species, because of Avicenna's idea that disembodied souls continue in their individual existence, and have their own specific essence. Angels are formally different, that is, different in species, from each other.

7. Aquinas on the real distinction between essence and existence in creatures and the real identity of the same in God
1. For every x, if the essence of x [e(x)] is known and its existence or being [b(x)] is not,
then e(x) is not identical with b(x), i.e., in the essence and existence of x are really
distinct. [R(x)]
2. There are some things x, such that R(x)
3. There is at most one y, such that ~R(y), call it d
4. Therefore, for every x other than d, R(x)
5. Every x, such that R(x), must be caused by d
6. Therefore, d exists
Aquinas does not assume God's existence; it is not required for proving the distinction between essence and existence in all creatures

Even in the case of pure immaterial forms (e.g., angels) there is composition between pure subsistent form (nothing but the essence of the thing which is nothing but the thing itself) and an act of existence that determines and limits its own capacity.

This is why God's existence does not need a sustaining cause – for us, what we are does not account for the fact THAT we are.

God sustains our being – just as, if we turn off the light source, there is nothing on the projector screen.

There can be at most one thing in which essence and existence are the same thing. How many ways can we multiply things within a kind? (1) Through matter (individuals having same form are multiplied through reception of form in different parcels of matter). But the essence of material things are not their being because material beings are not pure being (they are in potentiality on account of their matter). (2) ... [?] (3) Being divided by additional formal differences.

These all involve potentiality, which a pure being cannot admit.

8. Aquinas on the provability of God's existence
Important Texts: Summa Theologica I, q. 2, art. 1, ad 1 (Damascene), ad 2 (Anselm)
Important Texts: Summa Theologica I, q. 2, art. 2, ad 2 (Damascene)

A demonstration is any valid, sound, non question-begging deductive argument
-Scientific demonstration must consist of perfect syllogism. The middle term must be the quidditative definition of the subject.
-two kinds of demonstration: demonstration why (propter quid) & demonstration that (demonstratio propter quia)

Pay particular attention to objections in first two articles: (1) Stance on the Hyperrationality of St. Anselm; (2) Stance on the Fideism of St. John of Damascus.
(1) St. Anselm says self-evident, once we understand the meaning of the terms. But atheists can simply refuse to think of God in the same way we believers think of Him. St. Anselm's argument cannot be universally persuasive, says St. Thomas, because there is nothing to compel the atheist to think of God under this precise description.
(2) Any scientific proof would need quidditative definition of God, which is impossible. But we can have a nominal definition, and argue the existence of the cause from the existence of its effects, without having a quidditative definition of God.

9. Aquinas' proofs of God's existence
Five Ways: Summa Theologica I, q. 2, art. 3, corp.

Summa Theologica I, q. 2, art. 1, corp.: God's existence is self-evident in itself, since the subject and the predicate have the same signification. However, that God exists is not self-evident to us.

First Way: There has to be a Prime Mover, because no infinite series of causes is possible.

10. Aquinas on divine simplicity
Important Texts: Summa Theologica I, q. 3.

God is present in every creature, but not as a component part. He is not composed of matter and form, essence and existence, subject and accident, etc.

When Aquinas says Wisdom is the same as Power in God, he is using them as common terms for individualized instances. Just because Wisdom is not identified with Power in general, this does not mean that this Wisdom cannot be identified with this Power.

11. Aquinas on definition and essence
The essence of the soul is the substantial form of the body to the exclusion of its accidents (acts of thinking, willing).
Socrates is what his quidditative definition of his proximate species (man) signifies in him.
Socrates's forma totius is signified by his definition.
Socrates's quiddity is signified by his definition.
Socrates's soul is the substantial form of the matter of his body.
Socrates's body cannot be prime matter (Socrates's body is not his prime matter), but prime matter is a part of Socrates's body.

Socrates's body is Socrates, but Socrates's soul is not. Socrates's body, in the sense in which Socrates is a body, is Socrates.

It is true that Socrates is a body (non-exclusive sense, signification includes 3D-ness but does not exclude other essential perfections). It is also true that Socrates has a body (exclusive sense- sense excluding other essential perfections).

A term used in two different senses is equivocal.

There is only a distinction of reason between Socrates's animality and Socrates's humanity.

12. Aquinas on the immateriality of the human soul

Is the human soul a material form? Yes, because it is the substantial form of the human being (its being consists in informing the matter of the human body).

St. Peter is body & soul. His soul is only a survival of part of the human person St. Peter. But we can say, "St. Peter pray for us" by way of synecdoche (pars pro toto = part for the whole).

13. Aquinas' arguments for the immateriality of the intellect
Important Notes: "Intellective Functions According to Aristotle"

Since the materiality of cognition entails its singularity, the universality of cognition entails its immateriality. This is the main contrapositive implication that Aquinas uses in one of his arguments for the immateriality of the intellect.

Intellect is dependent for its input on the brain (in the form of phantasms), but not for the actuality of its operation or existence.

Intellect must be immaterial because it has its own immaterial activity that it cannot share with the body. This cannot take place in matter like seeing, sensing, walking, which activities necessarily occur in matter. The activity of kicking is nothing but the activity of the leg itself. Our brain assists in our thinking, but thinking is not the activity of our brain. On the other hand, kicking is not just assisted by our leg, but is performed by our leg.

The human intellect is a form of a form, and not a form of a composite substance. The intellect is not inherent in the soul-body composite, but inherent in the soul alone.

The intellect is an accident of the human soul, just as heat is an accident of fire. The agent intellect is an active power, the potential intellect is a passive power. These powers belong to Aristotle's classification of accidents.

The separate soul would naturally cognize only universals. Singular cognition is tied to the materiality of the internal & external senses.

Siger: inherence and subsistence are incompatible modes of being; therefore, if the intellect is immaterial, then it must be subsistent. The soul and the intellect are separate, since each is subsistent.

First argument from universality of scope of human thought starts with idea that human intellect is capable of forming some universal representation of some universal concept of all material natures. Any cognition consists in the reception of the form of the matter of the object, without the reception of the matter itself. The cognitive power cannot have any of the forms that it is capable of representing, just as the eye cannot have any of the colors in order to be receptive of any of the colors it sees (pupil colorless for this reason). If the intellect is representative of all material natures, but cannot have in its own nature, any of the forms it is capable of representing, it cannot have any of these material forms in its own nature. Thus the intellect cannot be inherent in matter (cannot be a material form), so it is immaterial.

14. Aquinas on being and goodness
"Goodness and being are really the same, and differ only in idea" (Summa Theologica I, q. 5, art. 1, corp.)

15. Aquinas on the relationship between positive law and natural law
"Natural law is the measure of the justice of positive legislation."

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