SP is just being a good scientismist.

Cause in science

This last notion of causality, as mere sequence, but without any idealistic ground to account for it, is that which principally obtains in current science. A given event, in the instant A, is uniformly followed by a second given event in the instant B. No implication of power, or dependence, is conceived or stated. Similarly, a group of events, in one instant, is followed by another group in the next; the total sum of things comprising the world is succeeded by the total sum of things comprising the world in two succeeding instants. In all these cases, as far as they are considered by science, the event or events of the prior instant are always the cause of what follows, provided the succession is invariable. Thus the same thing may conceivably be, and is sometimes said to be both cause and effect, identical in all respects but that of succession in time. There need be no necessary contradiction between such a view and that of philosophy; for science, as such, does not consider the questions of metaphysics or seek to determine the essential causes of beings. A relationship, given that it is invariable, as the unconditional constant succession of John Stuart Mill, between the two or more phenomena, is all that science demands and, under the particular abstractions with which it deals, this is enough to ensure scientific results. A knowledge of the conditions of the existence of certain phenomena is the principal aim of science;

I haven't read the entire thread, but it seems to me that SP is denying that there is any such thing as an "essentially ordered" causal series; there are only "accidental" series. His reasoning appears to be the following:  given that there is always a time lag between successive elements in any causal series, and that, per Newton, inertia holds, it follows that there is no need for a "first mover" - the first mover in any series is to be found by tracing the series back to the big bang and beyond.

Is that a fair summary, SP?

Feser has addressed this objection in his blog many times. Here's a quote taken from his post "science dorks" (as this is only my second post, I wasn't allowed to post the link):

For example, years ago I had an atheist reader who was obsessed with the idea that there is a slight time lag between the motion of the stick that moves the stone, and the motion of the stone itself, as if this had devastating implications for Aquinas’ First Way.

Not sure if that exchange between Feser and the "science dork" is in any of his previous posts, but the first 3 replies in the combox are worth reading (particularly the one from Scott).