Going back to the OP, I think the problem with all of this has to do with our definition of "the present." At least for me, the problem is that if I'm not careful I assume a Newtonian notion of both space and time . . . what I might consider a common-sense view (regardless of whether or not, historically, that's been the common sense view). I have to work hard to remember that voids are not really things and that time doesn't exist as a discrete entity. The result of that is that it's easy for me to think of the past, the present, and the future as discrete, real things -- i.e., as in a platonic notion of time. So it's easy enough by thinking about relativity to see that, for some observers, thinks that one regards as past another will regard as future, and that quite literally the order of events themselves can be perceived differently. All of that has to do with your frame of reference and is completely consistent with an A/T notion of time. What it is not
consistent with is a Newtonian, or what I consider a common-sense, view of time.
So, again, that's easy for me to see about the past and the future. I have to work extra hard to remind myself that the present is just the same way. I can't define "the present" in a Newtonian sense, as if there were some universal "now." I think it is important to remember that everything really and truly does have it's own now, and due to the way the universe is structured (and this will get us to the wrongly labeled speed of causality, as I far as I can tell), because nothing material moves at this so-called speed of causality but is instead impeded by mass, and because most everything in our daily lives is far larger than quantum level stuff, the bottom line is that our normal lives tends very much to be consistent with regard to our temporal references. That goes back to my comments to CC. It's just a fact that everything in my daily life is so vastly closer together in distance than the speed of light that, and given the scale I normally operate at (inches, feet, and miles; seconds, minutes, hours, days, and years), that everything is so very consistent.
That can make it easy to think of "the present" as this thing that all reality has to share. But that's just not true. If time is the numbering of motion before and after, and if things
move, and if things
stand in relation to one another and therefore a temporal relation to one another, then everything really does have it's own time. "The present" is massively subjective. It is objective insofar as I truly am in act at this way, but it puts the cart before the horse to say that I am actually this way right now
. More precisely, that's trivially true. That's what "right now" is. It is the way I actually exist. The future is the way I will or could exist when that potentiality gets reduced and the past is the actuality that was that no longer is. So "nowness" derives from
causality. That is, the present itself derives from
my state. It isn't vice-versa. But then you have to add the very important fact that I don't perceive my "nowness" in the now. The very act of perception is a change, and thus to perceive what I am now is, by the very nature of the perception, to perceive something that was
. And thus, in a very real sense, my present experience is necessarily and always the past.
By simple analogy, we all know that the stars, as we see them today, is not how they are today. We're actually looking back in time. But in the same way, my perception of "now" is what was, not what is. So the subjective present is the objective past. The objective present is absolutely imperceptible due to the nature of human intellect, or indeed of any intellect that does not immediately apprehend some reality (which I take to be everything but God, although perhaps someone could argue that aeviternal beings could so perceive reality--I haven't studied that enough to know).
What I think I'm seeing then, is that "the speed of causality" is very poorly worded--not true as stated, in fact. It's meaningless, for all the reasons I've been arguing. What we ought to say is that, given the nature of mass itself there must be cosmic speed limit (in short, it is not true that the distance between two objects is infinitely divisible, and that must be true (so see Xeno's Paradox - or this Space Time video
that explains it). Just like at a certain "closeness," reality becomes "blurry," at a close enough measure of "the present," reality becomes "blurry." That is, again, the closer you get to that speed limit, the blurrier things get.
I think that's what this whole "speed of causality" thing is actually trying to measure. At this speed of light/causality, what you actually have is unimpeded change . . . the effect of A on B without anything (i.e., mass) to hinder it. At such a speed, causality really would be instantaneous. And, indeed, as I think is well known, if the speed of light were infinite, then there would be no mass, no universe, no time, because everything would be instantaneous. Ironically, Newton's absolute present would leave us with an instantaneous and so non-existent universe! But start adding mass and you start adding impedance to change. And that makes sense, as Aristotle and Aquinas tell us that for any hylomorph, the whole is moved by the parts. The more mass, the more parts. The more parts, the more has to be moved for the whole to move. The more change necessary, the more time passes. Thus, the larger the object, the slower it goes, i.e., the more time it experiences. That's why a photon, which is massless, wouldn't experience any time (to anthropomorphize that a bit).
I claim, then, that causality does not have a speed, contrary to the original video. Rather, what happens is that we can calculate the rate of change for that which has no mass and then assign it a "time." The time can only be assigned because we are massive (that is, we have mass, not that we are huge). The cost of this is that I have to give up my notion of "the present" as some absolute thing, because I only have a "present" insofar as I have time, which is to say, insofar as I am a massive thing that is changing.
I also am wondering if this isn't what underlies some of the difficulties we have in discussing QM with the difficulty of measuring a particles' velocity and position with precision. What I just said above would presume that photons (say) don't actually have a present--at least, not from our perspective
. It is certainly true that the photon is in act, and so has an objective present, but it can't have the subjective present I discussed earlier for all the reasons I've already mentioned. What that means that when I ask where a photon is "right now" or I ask where it is "right now" I'm asking it for it's temporal relation to my
present. But that is just impossible. It's impossible to get both, anyway. Because if the photon has no present (for me), then in measuring it, I am giving
it a present (for me). But since having a present presumes
a causality, I have to ask what it was that caused it to have a present for me. And that cause is . . . ME! In measuring or observing it, I gave it a temporal relation. (And given the important of the Planck constant in the connection between the objective and subjective present (again, see the video linked above), I'm not surprised when Heisenberg gets his uncertainty principle via the said constant.)
So I guess I lied when I said I think the two are easily reconcilable. They aren't. But bottom line is that as far as I can tell, it's important to let go of a universal notion of "the present" and to recognize that the phrase "speed of causality" is meaningless, that instead, what we're measuring is our perception of unimpeded change, how that looks to our frame of reference. Taken one way, it really will be absolute for any frame of reference, because non-impeded is just non-impeded! But taken another, from the thing not being impeded (i.e., a photon, or something inside a singularity), it really would be different.
If I'm anywhere near the ballpark of being right, what blows me away about this isn't that we can understand these modern scientific claims in light of Aristotle and Aquinas, but rather that these principles (not the math, though) seem embedded in their very thought process. In other words, I don't think I'm reading science into the A/T theory of time, here. Rather, I think think this is all just a rather natural outworking of the A/T theory of time (and so causality).
Or, of course, everything I said above could be utter nonsense . . .