– Objection: The First Way concludes not to pure act, but to something that is immobile with respect to the motion one starts with. The first mover of an object that changes place can still have the potency to heat up or cool down.
Response: This is true but it misses the point. Something that causes motion without being in motion is self-evidently non-natural. It would be a soul that did not move along with its body; a force that did not move along with what it was forcing; a skyhook that didn’t have to ascend with what it lifted, a magnetic field that didn’t flow and warp with the iron it tugged, etc. It’s evident that such a mover can’t be a body (and so is a spirit). Given this, things have to be present to him as things are present to spirits, i.e. by being known.
-If our explanations of motion give no account of the first mover, their logic is identical to resting the world on a stack of turtles. The whole problem with the turtle is that just as one can’t explain motion by mobile movers, he can’t explain stability by stabilized stabilizers.
–Objection: the point of science is not to reduce to ultimate causes but to co-ordinate phenomena to each other.
Response: False – and in fact deeply false in a way that doesn’t understand the first thing about science. Energy is not a phenomenon. Who observes a single reality that can be cashed-in from motion to heat to friction to height to chemical bonds? Feynman is right that it is unthinkable that a single reality should be preserved though all these changes.
It would be truer to say that science continually tries to explain the concrete through the abstract, i.e. phenomena in light of the ideal or simple form. The Thomist quip about “reducing all causes to material and efficient causes” is ill-considered. Science wants to reduce everything to formal causes: abstractions like laws, idealizations, blackboard realities, etc. The First Way is thus in keeping with the scientific spirit as it’s actually practiced, as opposed to the press junket that talks about limiting ourselves to the observable.
-Motion is relative only when we cease to consider the asymmetry of action and passion. I am not “moving with respect to” anything when I act. Pushing is not just the translation of matter (which is relative) but an activity exerted on something. It makes no difference to a physicist whether I push down a woman or she pulls down my hands when she throws herself down, but to say that there is no physical, asymmetrical reality to observe here is nonsense.