Proof 1 of 5
The proof for the existence of God which I am about to lay before you is one of the most famous and celebrated in history. It is considered rationally valid by serious logicians. It is without legitimate refutation -except for by those who reject classical reason altogether such as Immanuel Kant and Frederick Nietzsche. Nearly three thousand years old, this proof is still celebrated today as undefeated by all who respect classical reason.
The demonstration is grounded in the self-evident primary first principles of theoretical reason, not scripture. It is grounded in secondary self-evident first principles as well –that is, statements which are immediately understood to be true in-and-of-themselves, once the words that make up the statement are understood (example- halves taken from wholes leave halves, or the whole is greater than the part). It also holds true for tertiary and quaternary types of principles.
The demonstration appears originally in Aristotle (The Philosopher) who wrote the earliest known text on logic. It was constrained to the near east however until discovered by Adelhard of Bath in the twelfth century, who introduced it to the West for the first time. The Jewish rabbi Moses Maimonides gave it serious treatment during this same century. The demonstration found its first complete explication in St. Albert the Great in the thirteenth century, who taught it to St. Thomas Aquinas (The Angelic Doctor). Thomas included an exhaustive treatment of this proof in his magnum opus on Theology and Natural Law,Summa Contra Gentiles. This proof serves as one of The Five Ways –the official proves accepted by the Holy Roman Catholic Church and Protestants alike, the world over, for the existence of God. It may be said to be an explication of the Book of Wisdom and of St. Paul in the Book of Romans, that God can be known by His works, in the words of C.S. Lewis, “by the pattern which that heavenly wave left on the sand when it retreated.”
From the first proof one can learn some things about God, i.e. his “Oneness,” “Omnipotence,” and "Incorporeity." From other proves (The Five Ways) one can come to learn more about God. Once knowledge of God is exhausted by The Five Ways one must turn to other ways of knowing, like the The Negative Way (via negativa), The Affirmative Way (via affirmativa), and Knowledge by Analogy until at last one will reach the maximum conceptualization one can attain about the nature of God, without revelation.
This “First Way” (or proof) takes as its point of departure a consideration of cosmic motion and is given in many forms. This first form of the proof is given by two methods –Direct and Indirect. In this article I will only consider the Direct Method of Proof. Each form and each method of proof is sound in and of itself. Simultaneously each proof expands our understanding of the other. The Direct Method of Proof is one of two major Methods. Each Method in turn has multiple modes of demonstration, each of which begins from a different point in the argument. Together the many modes of demonstration feed into the two Methods. Thus, there are numerous ways of explicating the first proof -itself only one of many ways of proving the existence of God.
I will start by laying out the Direct Proof from Motion proposed by Aristotle (The Philosopher) and expanded upon by St. Thomas Aquinas (The Angelic Doctor) in eight parts, then I will demonstrate the sub-proofs taken for granted in the Direct Proof.
1. Our senses show that some things are in motion (whether or not one can trust his senses is addressed in the Suma Contra Gentiles in Book 2 here: http://dhspriory.org/thomas/ContraGentiles.htm
2. Things only move when potential motion becomes actual motion
3. Only something actually in motion can pass something potentially in motion into actual motion
4. Nothing can be at once in both actual motion and potential motion at the same time and in the same respect
5. Therefore nothing can move itself
6. Therefore each thing that is actually in motion is moved by something else already actually in motion
7. The sequence of motion cannot extend to infinity because then there would be no first mover and consequently no other mover, since all subsequent movers move only inasmuch as they are moved by the first mover
8. Therefore it is necessary to arrive at a first mover, put in motion by no other, which has no potential left that hasn't already been actualized, and is therefore Omnipotent. And since there is no divide between potential and actual this Being can be said to be One. And since no corporeal being is the cause of itself, since it is divided into potentiality and actuality and motion happens when a thing passes from potentiality to actuality, the First Being can be said to be Incorporeal. Here we have the three attributes of God, discernable in the first proof. (these attributes are also discernable in other proofs overlappingly)
Two propositions must be established to confirm the validity of the first proof, that-
1. We cannot go back to infinity in the series of movers and things moved
2. Everything that moves is moved by something else
Before defending these two propositions I would like to address the type of motion, the type of infinite series Thomas Aquinas and Aristotle among others have in mind.
Motion = Reduction of Potency to Act
For Aristotle and Thomas motion is defined in its most broad sense, that is, as the reduction of a potency to act. This definition of motion would include not only movement in the directional sense but general change or activation as well. For example, fire which is actually hot, makes wood, which is otherwise only potentially hot, actually hot. Thus, in this instance the fire actualizes the potential of the wood to become hot, burn and in effect undergo a substantial change to ash, rather than a merely accidental change (as if a piece of wood were merely cut in half and therefore remained wood albeit in a different pieces, shapes, and weights, etc.) Any change or movement is considered motion in the Aristotelian/Thomist sense since each includes the reduction of potency to act –a division which divides all corporeal being and establishes the reality of motion in the world.
Infinite Series- Per Accidens Causes vs. Per Se Causes
Per Accidens Causes-
A per accidens cause is not a pure cause but is instead called a cause because of some relation to a cause or because it is conjoined to a cause. For example, when Jacob begets Joseph, it is precisely Jacob who begets him, and not Abraham who begets him by using Isaac and Jacob as instruments. In causes per accidens each member of a series has its causal power independently of the earlier members. There may not be a need to trace any particular member’s action back to the activity of a currently existing first member in order to prove that a thing has a cause per accidens.
The type of infinite series referred to by Aristotle and Thomas here is not per accidens. In other words, Thomas is not referring to an infinite series regressing through time to a beginning point “in time.” In Thomas’s view, it is at least theoretically possible for a causal series ordered per accidens to regress to infinity, and thus have no beginning point. Although Thomas did not believe the universe regresses to infinity, he also does not believe it is possible to prove via purely rational argument that the world must have had a beginning in time either –a common misconception people make when interpreting The First Proof. Instead, Thomas is referring to a chain of causes ordered per se.
Causes per accidens may be said to be horizontal (one after the other each independent after being caused) and causes per se may be said to be vertical (in direct causes, each cause is conjoined to a direct effect and the cause happens simultaneously with the effect).
Per Se Causes-
In sharp contrast to per accidens causes, it is impossible to proceed to infinity in efficientper se causes. In per se causes each cause activates another’s potential nature (whether formal, virtual, or some other) turning possible-effects into actual-effects.
For example, a stone’s potentiality for motion is actualized by the arm, the arms potentiality for motion is actualized by the flexing of certain muscles, the muscles potentiality for flexing is actualized by the firing of certain motor neurons, the firing of certain motor neurons depends upon the state of the nervous stystem, which depends on its molecular structure, and so on until we get to the point where it all in turn depends upon the overall atomic basis of the molecular structure, which depends on electromagnetism, which depends on gravitation, which depends on the weak and strong nuclear forces, and so on and so forth, all happening simultaneously, here and now, as we are led ultimately to appeal to the reduction of potency to act vis-a-vis the existence of a being of ever deeper and more general features of reality –and the only way to stop this regress and arrive at a first member of the series is with something whose very existence, and not merely its operations or activities, need not be actualized by anything else. This would be something which, simply exists, without being made to exist by anything prior -something that is actual without being actualized. Something which is pure act, with no admixture of potentiality whatsoever.
Now that being which has no potency to actualize, could not possibly change or move. It is an unmoved mover. In other words since motion means reducing potency to act, and since the first mover is pure act, we can say the first mover is not divisible, but “One.” We can also say that the first mover is “Omnipotent.” Not only is the first mover not moved by another. It is unmovable.
Now that we have motion and the type of causes Thomas is referring to properly defined we can move on to establish the two propositions required for the First Way to be valid.
Aristotle proves the first proposition, which states that we cannot go back to infinity in the series of movers and things moved per se by three demonstrations.
1. Infinite Bodies Cannot Exist in Finite Time: If we go back to infinity in the series of movers and things moved, we must affirm that there is an infinite number of bodies, for whatever is moved is divisible into potentiality and actuality, and consequently, is a corporeal body.
Now, every body which is moved by something already moving per se, is moved at the same time. Therefore this entire infinity of bodies which move because moved must move simultaneously when one of them moves (they are all connected by virtue of the fact that they each move the next in the series and so on, here and now as per se causes).
But since each one of them, taken by it self, is finite, it must move in finite time, therefore the infinity of bodies which must move at the same time it moves, must move in finite time. Now this is impossible. It is impossible for infinite bodies to move in finite time.
What moves and what is moved must exist together, as can be demonstrated inductively by running through all the species of movement. It is therefore impossible to go back to infinity in the series of movers and things moved. Bodies can only exist together by continuity or contiguity. Since, therefore all these movers and things moved are necessarily bodies; they must form a single mobile whose parts are continuous or contiguous. Thus something infinite is moved in a finite time. Now in his Physics, VI, 7, and VII, I Aristotle has proved that it is impossible that infinity should move in finite time.
2. First Mover Disappears All Other Motion Ceases: The second reason proving the impossibility of infinite regression is this. When a series of movers and things moved are ordered, that is, when they form a series where each one moves the next, it is inevitable that, if the first mover disappeared or ceased to move, none of the rest would any longer be either a mover or moved. It is the first mover, indeed, which confers the power of moving on all others. Now if we have an infinite series of movers and things moved there will no longer be a first mover and all are intermediate movers. Therefore, if the action of the first mover is wanting, nothing will be moved and there will be no movement in the world.
3. Instrumental Movers Only Move If There is First a Principle Mover: The third reason is the same as the preceding one, except the order of the terms is reversed. We begin with the higher term and reason from there. The instrumental moving cause can only move if there exists some principle moving cause. But if we go back to infinity in the series of movers and things moved, all will at the same time be mover and moved. There will therefore be only instrumental moving causes, and, since there will be no principle moving cause, there will be no movement in the world.
Aristotle proves the second proposition, which states that everything that moves is moved by something else by three demonstrations, two deductive, and one inductive.
I. Here is the first which itself supposes three self-evident facts-
A. For a thing to move it self, it must contain within itself the principle of its movement, otherwise it would be moved by something else.
B. For a thing to contain within itself the principle of its movement it would have to move its whole self at once and not by one of its parts, as the animal is moved by the movement of its foot, in which case one part moves another part, which in return moves the previous part and so on.
C. Anything that is not an “unmoved mover,” that contains within itself the principle of its movement must be divisible into parts, since whatever moves is divisible into potential and act, and therefore must pass from potential to act in order to “act”-ually move.
These granted we can show that nothing that is divisible into parts can move itself, since each part would depend upon the part before until we reach the first mover. It is only possible therefore that the first mover is not divisible into either parts or act and potency. Thus, “Oneness” and “Omnipotence” are necessary attributes of the first mover –whom we call God.
1. If we imagine the type of thing that could move itself it would have to move itself wholly at once, not in parts. If indeed one part were in motion and the other part at rest, it would no longer be the whole thing itself which would be moving, but one part would be moving another which would in return move the previous part and so on, as in the case of the animal. To say it the opposite way, nothing whose rest depends on the rest of another moves itself.
II. The second demonstration of this principle is an induction. It is self-evident that whatever is moved per accidens is not moved by itself. Its motion depends on the motion of another. This is also self-evident in anything that is subject to movement contrary to its nature or “violent motion.” This is also self-evident in anything that moves according to its nature and contains within itself the principle of its own movement in the weak sense (locomotion) (as in animals) but are not the per se first cause of their motion, as in in the strong sense.
Now whatever is moved is moved by itself or by accident. If it is moved by accident it is not moved by itself. If it is moved by itself it is moved either violently or by nature. If it is moved by nature, it depends upon an infinite regress of causes per se, which as we have established, is impossible, or else a First Cause (Unmovered Mover), as in the case of the animals, thus whatever is moved is moved by another.
III. Nothing is in potency and act at the same time and in the same respect. But everything is in potency insofar as it is moved, for movement is the act of what is in potency inasmuch as it is in potency. Now whatever moves is, in so far as it moves, in act. Therefore nothing is at the same time mover and moved, and consequently nothing moves itself.
Thus are the two demonstrations proved that we found at the basis of the first demonstration by which Aristotle and Thomas established the existence of a first immobile mover. The same conclusion can be established Indirectly, that is, by establishing that the proposition “whatever moves is moved” is true neither by accident nor by itself. There are other ways of establishing the necessity of a first mover as well. each proof is feeds into the overall First Way.