Hi Ken,
Please excuse me if I don't address points in the exchange you've had with Ian. I want to be as brief as possible in response to what you wrote to me. I do, however, need to provide some context for my criticism of your view.
My greater claim is that all accounts of any sense of temporal passage that I've read in my physicist's survey of the philosophy literature are abominations. They're no better (and maybe even worse because they're so explicitly wrong) than the physicist's foggy conception of temporal passage. All is a mess. And I think "subjective updating" falls right into this catagory. (Strong claim--and fightin' words indeed--so please allow me to explain. The upshot will be that you'll either see an error in a view that you support, that you weren't aware of before, or, by understanding my point, you'll be able to explain to me how subjective updating doesn't fall into this category).
More specifically, I claim that all accounts (that I've read or heard) of the presentist viewpoint, whether in favour or against it, make a very specific (and often explicit) error, which has confused the issue to the point that I do feel justified in calling these accounts "abominations". Because of this error, many--and then in light of relativity, many more--have committed what I'll call the Abortionist Fallacy (meant in the more general sense of "a failure to develop to completion or maturity") of arguing *from those erroneous descriptions* that presentism is false. In fact, the usual claim is that temporal passage is not as we commonly think of it--the most famous example being perhaps McTaggart's argument for the unreality of time.
Before I get to my main point, which is very simple, please let me explain what I mean by "Abortionist Fallacy". Consider the following (which I claim to be true): The purpose, or grand aim, of thought experiments, should be to make perfect sense of things that are not intuitively obvious to begin with (cf. Galileo's boat experiment). If this statement is true, then due to his prior definition of simultaneity, Einstein committed the Abortionist Fallacy when conducting his special relativistic thought experiments, from which he inferred the relativity of simultaneity, and therefore simply aborted the sensible notion of objective passage (cf. my first post above).
So, now: what's the one thing that's wrong with all attempts to describe temporal passage? It's simply the all-too-common idea that events (the things that happen, occur, take place, etc., which make up space-time) *exist*.
The error occurs whenever verbs are used to describe events. This is because all verbs--and particularly the copular verb 'is', 'will be', 'was', etc.--smuggle a sense of temporal passage into the mix because every last one of them has existential meaning. People are already dead wrong when they say, for instance, "look at this worldline, with a few points (t_1, t_2, t_3, etc.) labelled on it. The fact of the matter, in the presentist view, is that *at* t_1, only t_1 exists; at t_2, only t_2 exists, and t_1 no longer exists. The reductionist, or minimalist viewpoint--and what follows from McTaggart's argument--is that all t exists; i.e. the object represented by the worldline has temporal parts; etc."
I'm claiming that "exists" in the first and second sentence, as well as "has" in the second sentence, are completely wrong words to use, which totally confuse the meaning.
People might refer to events at certain times as being "real" or "Real", in a sweeping spotlight sort of way (the past is "real" in some sense, because I can talk about it, etc.). But the thing that actually matters isn't the big "R"/little "r" distinction. The thing that actually matters is the use of "being", which carries existential meaning.
The reason is simple: in a Newtonian conception of reality (my previous essay shows that relativity presents no real problem either, as long as "simultaneous" isn't mis-defined a la Einstein), how many dimensions are there in the physical description of "this chair exists here?" Since the chair's a 3D object, I hope your answer is "4D" (otherwise we've got an even bigger issue; cf. quote from Einstein's autobiography, above). Similarly, when we say "t_1 exists" or "all t exists" or "an object has temporal parts", or "an observer's subjective knowledge updates", we smuggle in a further dimension.
Just as "the existence of a 3D block" requires a fourth dimension in the physical description (even if the block doesn't change, still "while changing it exists"--Heraclitus), or the "existence" of an event needs 1D in order for the event to be described as something that exists, so the idea of events in 4D space-time as "existing" requires a 5D description. In essence, when we say (or think) "Jan 10, 1982, 1:26:32 exists", we think of the 3D world on Jan 10, 1982, at 1:26:32, as *existing* (i.e., when we say "is", "was", etc., we impose another dimension in the conception of that *instant*). The dimension in which events are described to "exist" is a hyper-time dimension, above and beyond the time-dimension describing the 3D universe's existence.
No one in their right mind has every supported this view outright (except maybe science fiction writers and growing block supporters like Ellis--although there's an argument that he's therefore perhaps *not* in his right mind), yet what I'm claiming is that when people assume a "third person"-view of eternity, a "view from no-when", a "God's eye-view", there is an overwhelming tendency to think that "God", the "third person", *exists*. Then the confusion sets in. Greene very explicitly describes the frozen block as something that exists, for example, patently assuming this hyper-time-dimension.
Now, how does this ubiquitous error factor into our debate? Basically, when you think that something subjectively updates their knowledge of the block, I'm saying you can't but assume such a hyper-time dimension. If everything really is singularly on par, you simply can't get this updating of knowledge within the block, any more than a fish can swim a distance through water, or electricity can flow through a wire, in an *instant*. In the sense of this hyper-time, the entire block has to be instantaneous, and therefore perceptions of it can't crawl along it and update.
When you describe reality as all of eternity, all four dimensions of the physical description of events that occur in reality, *at-once*, assuming a "God's eye view" of all the events that occur, you simply can't turn around and claim that your "God" exists *without adding the metaphysical structure associated with that*.
Parsimony is supposed to favour the block universe view of reality, which doesn't assume the extra structure of "3D space that exists"--i.e. a foliation--but what I'm saying is that "blockers" really don't have the more parsimoneous theory anyway. In fact, the view that all of space-time exists (Greene's view, etc.) assumes the same amount of structure in the sense that it assumes that something (of any dimension) *exists*; but because the thing it assumes exists actually has one higher dimension, it actually assumes *way more* structure. That's argument 1 against the "Humean minimalist" view--i.e., it's not actually minimalist at all.
Argument 2 is that the structure in the "anti-reductionist" view that "minimalists" want to do away with--viz. the foliation of space-time--is actually supported by cosmology anyway, so it's really a non-issue in the first place, if you take empirical evidence to be the supreme arbiter.
That's pretty much my argument in a nutshell. I don't think I'm committing any of the errors that you mention, but simply saying that I don't think you can get what you want to get without committing them yourself. I'm ready to listen, though, if you think you can get out of argument 1. Then, even still, I think I win by argument 2, since empirical evidence is supposed to trump all. In order to argue against me there, you'll have to overturn a whole area of physics--but still, I am willing (eager, in fact) to listen.
Best,
Daryl
