This is the problems that I see with the "Argument from motion"
First of all, it assumes that 'rest' is the default condition of things. This can not be shown to be true, and indeed, there is nothing we can look at this is totally at rest. Motion is basically how things are relative to each other, This argument is based on the Aristotle's concept of the Aether, which has been proven to be false.
So, it starts off with assumptions that not only haven't been shown to be true, but have actually been shown to be false.
Next, it assumes that there is one 'unmoved mover', and then labels this 'unmoved mover' as god. It makes the assumption that there can only be one source for making things move, and then uses a leap of logic to label this as god. This is the logical fallacy of special pleading, following by 'defining' God into place, without giving any reason to call it God.
All in all, it is not convincing, because of not only the logical flaws, but because the axiom on which ti is based has been positively proven to be false.
Here is what I think-
His physics is not that far off, though he didn't have the benefit of knowing what we know today.
We believe that entropy increases, and this is the natural direction of things. As such, in a closed system when entropy increases, the energy gets distributed or spread out, so that local concentrations of higher energy are reduced, until the whole system is equalized. One could call this the default condition of things.
Entropy can decrease, but in order to do so the energy has to be rearranged by an external force, which requires the addition of new energy.
Aristotles aether has been debated, refuted, reincluded and refuted again throughout history. The aether is an invisible medium made of some special substance that has the ability to transport energy through what would otherwise be empty space. Einstein changed his mind on this a few times, I think. This had some relation to his theories of a cosmological constant.
Albert Einstein in 1920: ”We may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an Aether. According to the general theory of relativity space without Aether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this Aether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it.” [13]
Paul Dirac wrote in 1951:[7] "Physical knowledge has advanced much since 1905, notably by the arrival of quantum mechanics, and the situation [about the scientific plausibility of Aether] has again changed. If one examines the question in the light of present-day knowledge, one finds that the Aether is no longer ruled out by relativity, and good reasons can now be advanced for postulating an Aether. . . . . . . .We have now the velocity at all points of space-time, playing a fundamental part in electrodynamics. It is natural to regard it as the velocity of some real physical thing. Thus with the new theory of electrodynamics [vacuum filled with virtual particles] we are rather forced to have an Aether".
https://en.wikipedia.org/wiki/Aether_theories#Conjectures_and_proposals
Today we have dark matter and dark energy theories to account for the apparent missing mass that confounds our observations of objects in space, like the rotational velocity of galaxies. The dark matter cannot be seen or measured, but it pervades everything everywhere and makes up the bulk of material in the universe. That sounds like an aether.
In electronics we talk about the
transmission impedance of free space, as a model to describe how radio waves propagate through an apparent vacuum.
These theories imply that there is no such thing as empty space. Vacuum has energy.
Coming to the issue of whether there needs to be a "first mover" or not, I would say from a human perspective, that is to say cause and effect, it seems completely reasonable. The alternative is harder for ordinary people to grasp.
