Ways of Knowing

Aquinas2.24.10

Quiz1. How many proofs does Aquinas offer for God’s

existence?2. T/F? - According to Aquinas, God is so different

from humans, it is impossible to talk about God.

Review• Aquinas• arguments• philosophy and theology• the existence of God

Today• faith, knowledge, and the existence of God• Aquinas’ five ways• questions and objections• talking about God

1. Man is directed to God as to an end that surpasses the grasp of his reason. (Final cause)

2. An end must be known in order to direct thoughts and actions.

3. Knowledge of this end is unclear, at best. Divine revelation is necessary.

Faith, knowledge, and God’s existence• articles of faith• preamble to the articles• nature and grace

Articles of faith“It seems that the existence of God cannot be

demonstrated. For it is an article of faith that God exists. But what is of faith cannot be demonstrated, because a demonstration produces scientific knowledge, whereas faith is of the unseen…” (451)

Preamble to the articles “The existence of God and other like truths about

God, which can be known by natural reason, are not articles of faith, but are preambles to the articles” (452).

Nature and grace“[F]aith presupposes natural knowledge, even as

grace presupposes nature and perfection the perfectible” (452).

Can you prove that God exists? “When an effect is better known to us than its

cause, from the effect we proceed to the knowledge of the cause. And from every effect the existence of its proper cause can be demonstrated, so long as its effect is better known to us; because, since every effect depends upon its cause, if the effect exists, the cause must pre-exist” (452).

The five ways• motion (change)• causation• contingency/necessity• gradation• governance

Motion*1. Things are in motion.2. Things move when potential motion becomes actual motion.3. Only an actual motion can convert a potential motion into an

actual motion.4. Nothing can be at once in both actuality and potentiality in

the same respect 5. Therefore nothing can move itself.6. Therefore, whatever is in motion must be put in motion by

another.7. The sequence of motion cannot extend back forever. Therefore it is necessary to arrive at a first mover; this

everyone understands to be God.

*Argument analysis modified from that of Dr. Theodore Gracyk of University of Minnesota, Moorhead.

Efficient cause1. We perceive a series of efficient causes of things in the world.2. Nothing exists prior to itself.3. Therefore nothing is the efficient cause of itself.4. If a previous efficient cause does not exist, neither does the

effect.5. Therefore if the first thing in a series does not exist, nothing

in the series exists.6. The series of efficient causes cannot extend infinitely into the

past, for then there would be no things existing now. Therefore it is necessary to admit a first efficient cause, to

which everyone gives the name of God.

Contingency1. We find in nature things that are possible to be and not to be,

i.e., contingent beings.2. Assume that every being is a contingent being.3. For each contingent being, there is a time it does not exist.4. It is impossible for these always to exist.5. Therefore there could have been a time when no things

existed.6. At that time there would have been nothing to bring the

currently existing contingent beings into existence.7. If so, nothing would be in existence now. (This is clearly not

true.)8. Therefore not every being is a contingent being. Therefore some being exists of its own necessity, and is the

cause of all others. This all men speak of as God

Gradation1. There is a gradation to be found in things: some are

better or worse than others.2. Predications of degree require reference to the

“uttermost” case (e.g., a thing is said to be hotter according as it more nearly resembles that which is hottest).

3. The maximum in any genus is the cause of all in that genus.

Therefore there must also be something which is to all beings the cause of their being, goodness, and every other perfection; we call this God.

Governance 1. We see that natural bodies work toward some goal,

and do not do so by chance.2. Most natural things lack knowledge. 3. But as an arrow reaches its target because it is

directed by an archer, what lacks intelligence achieves goals by being directed by something intelligent.

Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God.

Some questions• How did Aquinas intended these “proofs” to work?• Do they stand alone? • Is there a progression? • Do they mutually support each other? • Could you find some of the convincing, but not the

others? • Are some these proofs too historically conditioned,

using out-dated notions of motion/causation/purpose?

Some objections1. The Universe Just Is

The universe is "just there, and that's all" (Russell).2. Explaining the Individual Constituents of the Universe is

Sufficient When the parts are explained the whole is explained (Hume).3. The Causal Principle is Suspect

There is no reason for thinking that the Causal Principle is true (Hume).

4. The Conclusion is Contradictory The cosmological argument presupposes the cogency of the

ontological argument. But since the ontological argument is defective, the cosmological argument that depends on it likewise must be defective (Kant).

Talking about God• univocal• equivocal• analogical

Talking about God“And in this way some things are said of God and

creatures analogically, and not in a purely equivocal nor in a purely univocal sense” (456).

For next class:

Review your readings and your notes to prepare for the review session.

Work on your paper.