“Do not heed by whom a thing is said, but rather what is said.”
(Saint Thomas Aquinas, O.P., [b. 1225 A.D. in Rocca Secca, Naples, Italy - d. Wednesday, March 7, 1274 A.D., in Fossa Nuova, Italy], Doctor of the Church, Letter to Brother John; emphasis added.)
Saint Thomas Aquinas' 5 proofs for the Existence
Based on our Observation of the Effects of God in this World.
Saint Thomas Aquinas, O.P.
[b. 1225 A.D. in Rocca Secca, Naples, Italy -
d. Wednesday, March 7, 1274 A.D., in Fossa Nuova, Italy]
Doctor of the Church
Saint Thomas Aquinas presents 5 arguments for the existence of God. He argues that God exists on the basis of:
If movement is not self-explanatory, whether the movement is corporeal or Spiritual, it necessitates a First Mover.Premises/Conclusion:
Premise 1. Things are in motion.Conclusion of Argument from Movement:
Premise 2. Motion is the reduction from potentiality to actuality. In other words, something moves if it changes from being potentially in motion to being actually in motion.
Premise 3. Only something in a state of actuality can reduce something else from a state of potentiality to actuality. In other words, only something actually moving can make something else change from potentially moving to actually moving.
Premise 4. A thing cannot be both potential and actual in the same respect. This means that a thing cannot both be potentially moving and actually moving concurrently.
Premise 5. Sub-Conclusion 1 from: Premise 2, Premise 3, and Premise 4 - A thing cannot move itself.
Premise 6. Sub-Conclusion 2 from: Premise1, and Premise 5 - A thing must be moved by something else.
Premise 7. The chain of movers cannot go on to infinity.
There must be a First Mover. This First Mover is called God.
Summary of the Argument from Cause, i.e. from an Uncaused Cause:
If interconnected efficient causes are here and now actually operating, air and warmth, say, to preserve my life, then there must be a Supreme Cause from which here and now these causes derive their preservative causality.Premises/Conclusion:
Premise 1. A thing cannot be the cause of itself.Conclusion of Argument from Cause, i.e. from an Uncaused Cause:
Premise 2. The chain of causes cannot go on to infinity
Premise 3. If there is no first cause, there would be no effects.
There is a First Cause. This First Cause is called God.
Summary of the Argument from Necessity, i.e. from Contingency:
If there exist contingent beings, which can cease to exist, then there must be a Necessary Being which cannot cease to exist, which of itself has existence, and which, here and now, gives existence to these contingent beings.Premises/Conclusion:
If once nothing at all existed, there would not be now, or ever, anything at all in existence. To suppose all things contingent, that is, of themselves non-existent, is to suppose an absurdity.
Premise 1. It is possible for anything in nature to be or not be, i.e. to exist, or not to exist.Conclusion of Argument from Necessity, i.e. from Contingency:
Premise 2. If it is possible for something to be or not to be, then it must have at some time not been, i.e. not existed.
Premise 3. Conclusion: If everything could be or not be, then it is possible that at one time nothing existed.
Premise 4. Things are brought into existence by something that already exists.
Premise 5. Conclusion: Premise 3, and Premise 4. If at one time nothing existed, then there would be nothing in existence now. But there are things in existence now.
Premise 6. Conclusion: So, there must be something which exists necessarily.
Premise 7. An infinite chain of necessary beings is impossible.
Something must have its own necessity. This something which must have its own necessity is called God.
Summary of the Argument from Hierarchy:
If there are beings in the world which differ in their degree of nobility, goodness, and Truth, it is because they have but a share, a part, because they participate diversely, in existence, in nobility, in goodness, and in Truth.Premises/Conclusion:
Hence there is, in each of them, a composition, a union, between the subject which participates and the perfection, existence, goodness, Truth, in which it is given to them to participate. Now this composition, this union, presupposes the unity of which it participates.
“Quae secundum se diversa sunt non conveniunt in aliquod unum nisi per aliquam causam, adunantem ipsa. - Things which are different in themselves cannot unite into something unless something causes them to unite” (Saint Thomas Aquinas, Summa Theologica, Part I, Question 3, Article 7, I answer that, ..... Thirdly, ....)
Hence, at the summit, there must be one cause, one source of all perfection, who alone can say, not merely “I have existence, Truth, and life,” but rather “I AM existence, Truth, and life.”
Premise 1. Things are more or less good, true, noble, etc.Conclusion of Argument from Hierarchy:
Premise 2. Things can only be more or less good, etc. in relation to a standard of the maximum.
Premise 3. The maximum in any genus is the cause of everything else in the genus.
There must be some maximum being which is the cause of all the good qualities in every other being. This Maximum Being which is the cause of all the good qualities in every other being is called God.
Summary of the Argument from Design:
If one finds in the world, inanimate and animated, natural activities manifestly proportioned to a purpose, this proportioned fitness presupposes an intelligence which produces and preserves this purposeful tendency.
If the corporeal world tends to a cosmic center of cohesion, if plant and animal tend naturally to assimilation and reproduction, if the eye is here for vision and the ear for hearing, feet for walking, and wings for flying; if the human intellect tends to Truth and the human will tends to good; and if each person, by nature, longs for happiness, then necessarily these natural tendencies, so manifestly ordained to a proportioned good, a proportioned purpose, presuppose a supreme ordinator, a supreme intelligence, which knows and controls the raison d'etre of all things and this supreme ordinator must be Wisdom itself and Truth itself.
For again, union presupposes unity, presupposes absolute identity, which is why:
Premises/Conclusion:“A thing uncaused, is of itself, and immediately, i.e. without an intermediary, being itself, one by nature, not by participation” - “Quod causam non habet primum et immediatum est. Ens per essentiam et non per participationem” (Saint Thomas Aquinas, Summa Contra Gentiles, Book II, Chapter 15, § 2).
Premise 1. Things without intelligence act (for the most part) for the best result.Conclusion of Argument from Design:
Premise 2. Conclusion: Things act for an end.
Premise 3. An unintelligent thing cannot move toward an end unless directed by an intelligent being.
There is an intelligent being that directs all things toward their end. This Intelligent Being that directs all things toward their end is called God.