Unmoved mover
As formulated by Thomas Aquinas, the unmoved mover argument is summarized as follows:
- "Nothing moves without a prior mover. This leads us to a regress, from which the only escape is God. Something had to make the first move, and that something we call God."
The full passage is as follows:
"The first and more manifest way is the argument from motion. It is certain, and evident to our senses, that in the world some things are in motion. Now whatever is in motion is put in motion by another, for nothing can be in motion except it is in potentiality to that towards which it is in motion; whereas a thing moves inasmuch as it is in act. For motion is nothing else than the reduction of something from potentiality to actuality. But nothing can be reduced from potentiality to actuality, except by something in a state of actuality. Thus that which is actually hot, as fire, makes wood, which is potentially hot, to be actually hot, and thereby moves and changes it. Now it is not possible that the same thing should be at once in actuality and potentiality in the same respect, but only in different respects. For what is actually hot cannot simultaneously be potentially hot; but it is simultaneously potentially cold. It is therefore impossible that in the same respect and in the same way a thing should be both mover and moved, i.e. that it should move itself. Therefore, whatever is in motion must be put in motion by another. If that by which it is put in motion be itself put in motion, then this also must needs be put in motion by another, and that by another again. But this cannot go on to infinity, because then there would be no first mover, and, consequently, no other mover; seeing that subsequent movers move only inasmuch as they are put in motion by the first mover; as the staff moves only because it is put in motion by the hand. Therefore it is necessary to arrive at a first mover, put in motion by no other; and this everyone understands to be God. " from Summa Theologiae I.2 Article 3 [translation http://www.newadvent.org/summa/1002.htm] from New Advent
The mover in this argument refers to a cause of motion in the here and now. The argument only attempts to argue for a being that causes all changes in the universe without being changed themselves.
Concepts used to back the argument:
essential ordered series / causal series per se: a series where the motion of each mover depends on the previous mover such that if that previous mover were to cease then the mover and the following cease to move.
accidental ordered series / causal series per accedens: a series where each mover moves the next once and then is no longer needed for continued motion.
Aquinas likens the mover to a hand moving a rock with a stick where the rock moving depends on the stick moving which in turn depends on the hand moving.
This argument is one of the Quinque viæ, "Five Ways", or "Five Proofs".
Counter-apologetics[edit]
Many of the responses to the "uncaused cause" argument also apply to this one:
- The Thinker points out that under the B-Theory of Time, future states are not potential but actual hence change is instead from the actual of one time slice to the actual of the next.
- More generally under determinism things have only one possible potential which is actualized at the next moment.
- Why does the actualizer of a potential have to do so in a essential ordered manner when it could be actualized by something in a accidental ordered manner which then regresses infinitely?
- The Thinker points out that under the B-Theory of Time there are no potentials to actualize since a future state is not potential but actual hence change is instead from the actual of one time slice to the actual of the next.
- If nothing moves without a prior mover, then God must need a prior mover, as well. Otherwise God is nothing, which contradicts the conclusion. Thus, either the premise is untrue, in which case the argument is unsound, or the conclusion doesn't follow, in which case the argument is invalid. In fact, as stated, the argument is clearly self-contradictory.
- The argument exempts God via God causing change without being changed by anything else, hence "unmoved mover".
- Who created God?
- This argument only argues for an unchanged changer which is later defined as God.
- Which god? The argument does not demonstrate anything like God. The arbitrary use of the word "God" in the argument carries a lot of undesirable cultural baggage, denoting an intelligent being. If the ultimate cause of our universe turns out to be, say, a random quantum fluctuation, then that would be "God" by Aquinas's definition, but to call this phenomenon "God" would be very misleading.
- This argument argues for a unchanged changer who causes changes in the here and now who is later identified via later arguments with other beings established by the others ways to define the god of classical theism.
- Two bodies at rest will start to move towards each other due to gravity. They can be each other's first mover. Therefore, the prior mover requirement is unnecessary.
- This argument refers to an essential ordered series, i.e. a series of changes where one mover depends on the previous to move in the here and now.
- Pairs of virtual particles are created (and annihilated) all of the time, out of literally nothing. These particles affect each other's motion, thus disproving Aquinas's premise. Not all events necessarily have causes.
- More exotically, if time were circular (i.e., if time repeated every so often, so that the year 1 were also the year ten trillion and one), then every motion could have a prior cause without infinite regress. This does not seem to be the case, though.
- This argument refers to an essential ordered series, i.e. a series of changes where one mover depends on the previous to move in the here and now.
- Even if there is an infinite regress of causes, so what? The human mind is uncomfortable with the concept of infinity, but reality has no obligation to make us comfortable.
- The argument refers to a series where the causal power of a cause depends on the previous causes, which it's argued needs something not dependent on a previous cause to start the series.
- Why is a here and now mover needed, when the motion of something can be explained by mover in a temporal sense.
- The argument refers to a series where the causal power of a cause depends on the previous causes, which it's argued needs something not dependent on a previous cause to start the series.
Feser's Aristotelian argument[edit]
Edward Feser's Aristotelian argument is a hybrid of the above (Premise 4) and the Preservation argument (Premise 7)
- Change is a real feature of the world. (Premise)
- But change is actualization of potential. (Premise)
- So actualization of potential is a real feature of the world. (From 1, 2)
- No potential can be actualized unless something already actual actualizes it. (Premise)
- So any change is caused by something already actual. (From 2,4)
- The occurrence of any change C presupposes some thing or substance S which changes. (Premise)
- The existence of S at any given moment itself presupposes the concurrent actualization of S’s potential for existence. (Premise)
- So any substance S has at any moment some actualizer A of its existence. (From 4, 7)
- A’s own existence at the moment it actualizes S itself presupposes either (a) the concurrent actualization of its own potential for existence or (b) A’s being purely actual. (Premise)
- If A’s existence at the moment it actualizes S presupposes the concurrent actualization of its own potential for existence, then there exists a regress of concurrent actualizers that is either infinite or terminates in a purely actual actualizer. (Premise)
- But such a regress of concurrent actualizers would constitute a hierarchical causal series and such a series cannot regress infinitely. (Premise)
- So either A itself is a purely actual actualizer or there is a purely actual actualizer which terminates the regress that begins with the actualization of A. (From 9, 10, 11)
- So the occurrence of C and the existence of S at any given moment presupposes the existence of a purely actual actualizer. (From 6, 7, 12)
- So there is a purely actual actualizer. (From 13)
Counter-apologetics[edit]
- The Thinker points out that under the B-Theory of Time premises 2 and 3 are false since a future state is not potential but actual hence change is instead from the actual of one time slice to the actual of the next.
- More generally under determinism things have only one possible potential which is actualized at the next moment.
- Bradley Bowen points out that there are changes which are not actualizations of potentials such as turning water into wine.
- Graham Oppy criticizes premise 4 with the example of a chair with the potential to stay still without needing to be actualized by an external actualizer.
- Premise 7 which turns the argument into a variant of the preservation argument allows for similar responses to it.
- The assumption that existence of things need to be sustained can be challenged.
- Graham Oppy criticizes premise 7 along similar lines with his chair’s existence at a given time being fully explained by the actualization of the chair's own potential, at the previous time, to continue to exist through the given time, and the absence of anything that intervenes to prevent the realization of this potential.
- Why is existence a potential that has to actualized by an actualizer when it could be the other around where it is the cessation of existence requiring an outside cause?
- One can dispute that things even have a potential to cease to exist given that "destruction" is just rearranging something valued into something valued less.
See also[edit]
External links[edit]
- A Defense of Classical Theology (Part 1): The New Atheism and the Cosmological Arguments
- Five Proofs of the Existence of God
- Thomas Aquinas and the First Mover Argument, BBC Radio 4
