#9277
The God Hypothesis is the ultimate example of the
Fallacy of the Non-Testable Hypothesis. It can never be proven either way, although many have tried. Among those many are Thomas Aquinas who in the first few pages of his
Summa Theologica presented five such attempts. There are numerous translations of these arguments from sources such as Wikipedia and Dawkin’s
The God Delusion. The translation I refer to below is by the Fathers of the English Dominican Province as revised by Daniel J. Sullivan. Please note that the translation contains some unusual expressions but I have left the translation as-is.
The first of these is the “Argument From Motion.”
- It is certain, and evident to our senses, that in this world some things are in motion.
- Now whatever is in motion is put in motion by another, for nothing can be put in motion unless it is in potency to that towards which it is in motion.
- But a thing moves in so far as it is in act.
- For motion is nothing else than the reduction of something from potency to act.
- But nothing can be reduced from potency to act except by something in a state of act.
- Thus that which is actually hot, as fire, makes wood, which is potentially hot, to be actually hot, and thereby moves and changes it.
- It is therefore impossible that in the same respect and in the same way a thing should be both mover and moved, that is, that it should move itself.
- If that by which it is moved be itself moved, then this also must be moved 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 because as they are moved by the first mover, just as the staff moves only because it is moved by the hand.
- Therefore, it is necessary to arrive at a first mover which is moved by no other.
- And this everyone understands to be God.
The argument fails on several points. First is the premise “some things are in motion.” This reflects the 13th century view that there is some privileged frame of reference, viz., the earth. This notion survived the discovery, by Galileo and others, that the earth moves. The supposed privileged frame of reference became the aether. The Michelson-Morley experiment was designed to detect the aether but it failed. In his 1905 Theory of Special Relativity Albert Einstein explained the failure of the Michelson-Morley experiment by assuming that the aether does not exist. Einstein’s theory was confirmed in the 1920s, has been repeated confirmed ever since, is generally accepted by scientists today, and is unlikely to ever be overturned. Thus we are forced to replace Aquinas’s premise that “some things are in motion” with “all things are in motion and some things have a velocity of zero, which is still a valid velocity. For all things there is a frame of reference in which that thing has a velocity of zero.”
Second is the premise “whatever is in motion is put in motion by another.” Recall Newton’s three laws:
- Within a frame of reference a body will not accelerate unless acted upon by an external force.
- Within a frame of reference a body acted upon by an external force will accelerate at a rate proportional to the external force, inversely proportional to the body’s mass, and in the same direction as the force. i.e., f = ma. Note that the first law is a special case of the second law, viz. the case where the external force is zero.
- If a body exerts a force upon another body then the other body will exert a force upon the first body which equal in magnitude and in the opposite direction. i.e., action – reaction. This law is equivalent to the Law of Conservation of Momentum.
The second premise is a statement made by someone totally unfamiliar with the physical laws of motion. Of course we would expect this of someone who lived four centuries before Newton.
Aquinas’s second premise implies that motion is transmitted from one object to another by means of physical contact. Today we know that all acceleration is the result of one of the four primal forces: gravity, electromagnetism, the strong force, and the weak force, i.e.,
action at a distance.
Furthermore, at any given time absolutely every object in the universe is being acted upon by forces from every other object in the universe.
Brief digression: Consider the phrase “this cannot go on to infinity, because then there would be no first mover.” This is quite obviously a circular argument. Aquinas justifies his conclusion by using his conclusion as a premise. End of digression.
This declaration is the very heart of Aquinas’s argument. He is appealing to our supposed inability to deal with infinity. He completely ignores the possibility of causal loops, i.e., A moves B, B moves C, C moves A. Newton’s laws not only allow such loops but demand them, viz., action – reaction is a causal loop between only two objects. Furthermore, action – reaction demands causal loops between all possible pairs of objects in the universe.
But is an infinite sequence of events impossible? To answer this let us consider the first two of Kepler’s three laws of planetary motion.
- The orbit of a planet is an ellipse with the sun at one of the two foci.
- A line segment joining a planet and the sun sweeps out equal areas during equal intervals of time.
Kepler used data gathered by Tycho Brahe. How did he arrive at his laws? Brahe determined the position of each known planet at regular intervals (probably nightly). Kepler calculated the area of a triangle whose vertices where the sun and the position of the planet on successive nights. In a year’s data there are 365 such triangles whose areas are all approximately equal. If you could make measurements every 12 hours the data becomes even more precise. But the shape is an ellipse, not a 365 sided polygon, so there is always a bit left over. Kepler made the leap that if you could make an infinite number of measurements in a year the result would be exact, ergo, Kepler’s Second Law.
Newton proved that Kepler’s Second Law is exact. How did he do that? By discovering calculus. Calculus allows us to literally determine the total area of an infinite number of triangles with zero area. This is how we know that the area of a circle is the square of its radius multiplied by the number pi. There you have it, a real world infinite regress. At this point Aquinas’s argument falls completely apart.
A popular attempt at refuting the above is the red herring argument that Aquinas did not mean motion in the sense that we normally associate with the word, rather Aquinas meant any form of change when he used the word motion. If we accept this as a corollary to Aquinas argument then we must ask how many kinds of change are there? How many attributes can an object have which can be changed?
- An object has a position in space. A change in position is motion in the Newtonian sense.
- An object can have mass. This cannot change unless the object splits apart forming two or more objects (fission) or two or more objects can come together to form a single object (fusion). We must remember that mass and energy are the same thing (E = mc^2).
- An object can have a charge. A change in charge is an electric current. (This is actually an oversimplification of the principle but a detailed explanation is a one semester course in college physics so I will let it stand.)
With these in place (and possibly others) we can now re-state Newton’s Laws in terms of change.
- An object’s position, mass, charge, etc. will not change unless acted upon by an external force.
- An object’s position, mass, charge, etc. acted upon by an external force will change at a rate proportional to the external force.
- Momentum, mass, charge, etc. are conserved throughout the universe.
Finally Aquinas’s conclusion “And this everyone understands to be God” is simply not true.
