OK, I wrote this last Saturday, so the “nows” mentioned are earlier than the “now” as I post this, but that is perfectly OK, as my earlier-than “nows” have just as much existence as their later-than “nows.” :-)
Question for the audience, if those who believe in the present are labelled presentists, what do you call those who believe in the Block Universe? I leave it to you to be creative here.
This tells me two things. First, you have not read my posts, certainly not for comprehension. But you’ve already demonstrated this by repeatedly either mischaracterizing or ignoring my arguments.
If you had read my posts, or read them for comprehension, you’d know that the word you are looking for is
ETERNALISTS — eternal
ists believe in eternal
ism (the block universe). I’ve only used these words about two dozen times. And Petkov uses them in his paper, too.
The second thing it tells me is that you are totally unfamiliar with this topic, about a debate that goes back to the ancient Greeks. The first eternalist was Parmenides (though he did not call himself that). For if you knew about the topic, you would already know the word “eternalism.”
Before I make sweeping pronouncements about a subject, or even comment on it, I like to study it first, usually in depth. But that’s just me.
Now you write this:
I have consistently maintained that the present moment, the Now, alone exists, not the past or the future, for every object or individual. Your Now is fleeting, and it recedes into the past.
This Now is unique for every object. My Now is not your Now.
If this means anything at all, it sounds like Stein’s claim, which even presentists don’t like and which Petkov rebutted. But it seems to me that you do not even know what the existential claims of either presentism or eternalism actually
are. In the case of eternalism, you repeatedly claim that if it were true, we ought to be able to somehow “experience” the past and future along with the present, or become fortune tellers or some such, but I have already explained that this is NOT a claim of eternalism, and you just ignored that explanation too.
The difference between the presentist and the eternalist is not
epistemological. It is
ontological/existential. Things presentists and eternalists agree on:
That all we ever do, from moment to moment, is experience the NOW.
2. That each of us has memories of the past but not the future.
3. That each of us has, in the trivial sense you write above, our own “now.” For example, right now, I am at Coney Island, experiencing wonderful sand, sun, surf, beer, free WiFi, but also a blasted high wind that is ruining everything. You are somewhere else, having your own “now” experiences that differ from mine.
If this is all you mean by “presentism,” then we are in full agreement. But
actual presentism goes
far beyond this.
Actual presentism makes a profound
ontological/existential claim. A presentist would put it this way: “In a moment I am going to snap my fingers. When I do, I claim that we live in a universal single space with a universal agreed-upon time. This means that when I snap my fingers, there are events happening in China, on Mars, on planets in the Andromeda galaxy, indeed, every single place in the universe, that happen
simultaneously with the snap of my fingers. Ready?”
SNAP!
Now, of course, the presentist will not claim that he can
know what is happening “now” on Mars, or in Andromeda, when he snaps his fingers. We have no access to the data. He will just claim that something
is happening there, and everywhere else, that occurs
simultaneously with the snapping of his fingers.
This is what you need to be defending, if you are a presentist. The presentist claims that there are
distant present events, everywhere in the universe, that occur
simultaneously with the finger snap. This is presentism’s
core foundational claim, the exact
definition or presentism.
The problem for the presentist is that special relativity shows that its core foundational claim, its very definition, is
inconsistent with SR.SR shows that there are NO objectively real distant present events. If you want to talk about distant present events, you have to specify a frame — a plane of simultaneity. Since there can be an infinite number of different planes of simultaneity, there can be an infinite number of different NOWS, for different observers in relative motion.
Again, these different NOWS are not the same as the trivial observation that my “now” at Coney Island contains different experiences than your “now,” wherever you happen to be. Even though your “now” experiences and my “now” experiences are different, a presentist-favoring observer on Mars with his own “now” experiences could snap his tentacles, and claim that his tentacle snap, my enduring a bloody wind, and you doing whatever you are doing, happened
simultaneously, because the
only events that exist, for the presentist, are simultaneous for
everyone. Special relativity shows that this is not so — in fact, there are an infinite number of different temporal relations. Therefore, presentism makes an existential claim that is inconsistent with SR.
SR, however, is completely consistent with eternalism — the eternalist simply notes that infinite planes of simultaneity are infinite different slices of an existent 4D block universe.
Let’s again remember that the presentist claims that the past and future do not exist. So we return again to Einstein’s train model. Amy, on the train, sees a flash at the front of the train. Mary, on the ground, sees a flash at the front of the train, and another flash at the back of the train, simultaneously. Amy, sometime later, sees the flash at the back of the train.
Now according to the presentist, only the present exists, and not the past or future. This claim is straightforwardly leads to a conclusion that contradicts itself, which is that that flash at the back of the train both exists, and does not exist.
It exists, because a record of it exists at Mary’s eyes in her present. It does not exist, because the light at Amy’s eyes is in Amy’s future, but the presentist says the future does not exist and so the flash at the back of the train for Mary and then somewhat later at Amy’s eyes cannot exist. So it both exists, and does not exist, according to the presentist line of reasoning, even if the presentist does not notice this obvious contradiction.
You might counter that the presentist claims only that the flash does not (yet) exist for Amy, but will exist, when the future (for her) flash at her eyes somehow becomes part of her ever-changing present. But this evades the central problem, which is that you are claiming that an event that exists for Mary is nevertheless nonexistent because is in Amy’s future and the future does not exist. It cannot be the case that an event both exists and does not exist.
If the flash at the back of the train exists for Mary, and it does, then it exists, period. For her, at her eyes, it exists simultaneously with the flash at the front of the train when that flash is at her eyes. If presentism were true — that only the present exists — then it follows that the two flashes would be simultaneous for
both Amy and Mary. They’re not.
Since the back flash exists for Mary, it must also exist for Amy. For her, the flash meets her eyes later than the flash at the front of the train. The flash meeting her eyes exists in her future, which refutes the presentist claim that no future objects or events can exist because the future does not exist. Therefore presentism is false.
It’s irrelevant if Amy were to die before she sees the flash. The relevant point is that the flash
will happen at the back of the train, at a time later than Amy saw the flash at the front of the train. And because Mary saw the flash at the back simultaneous with the flash at the front, it is obvious that the back flash
exists, even if Amy never sees it because she dies or goes blind or whatever. Since the flash exists by virtue of the fact that Mary sees it, and since it must exist later for Amy, whether she sees it or not, it follows that the future (and the past) exist along with the present.
It is not I, as you charged earlier, but you, who are redefining presentism for your own purposes. To say that only “now” exists, is to say that there is a universal space with a universal plane of simultaneity that all observers agree on, as I explained above. That is the presentist stance. If you doubt this, I invite you to peruse the literature of presentists themselves. Their general response to SR is that it will be shown to be false and presentism will thus be shown to be true, or that metaphysical claims about reality should take precedence over scientific claims, so that even if SR shows presentism is false it should nevertheless be seen as metaphysically true.
Now you write:
So that’s it folks. Be of good cheer. Your future is open and it is for you to create with your choices. It has not been decided for you. This is the gift I leave for you. :)
You have ignored my careful modal logical demonstrations that an “open future” is not necessary for free will. It would be fine if you
disagreed with my arguments, and tried to rebut them, but you just ignore them, and simply pretend that no one has rebutted your claim that an open future is necessary for free will.
You write, about Sabine:
If she does believe that, [the block universe is real] she doesn’t say so in that post.
She says it in the OTHER blog post of hers I linked, “Now and Then,” in which she offers her views on WHY there seems to be a uniquely distinguished present, even though she says there isn’t.
… she says that SR is the only model that can resolve the debate on whether the world is three-dimensional or four-dimensional.
Yes, she does say that, and then she says that SR does not resolve the debate in favor of eternalism. However, she also says she is an eternalist — a believer in the block world — so clearly she does not feel that SR has resolved the debate in favor of presentism. So, here, I think, is what Sabine is saying: One must make a distinction between four-dimensionalism and eternalism, a careful distinction the eternalist often does not make, conflating the two as meaning the same thing. She is saying that SR shows that the world is four-dimensional, but it does not follow from this that four-dimensionalism entails eternalism (the block universe). How can this be so? Well, if you would actually like to study, for the first time, the subject you so freely discourse on, I suggest that you read
this paper. From that paper:
[one presentist response to special relativity] denies that SR, properly interpreted, involves or entails an assertion to the effect that there cannot be any absolute, i.e. observer-independent, simultaneity relation S. In fact, proponents of this strategy insist, what SR does prohibit is only that any such absolute simultaneity could not be detected in principle and would hence remain empirically completely inaccessible. Thus, SR does not preclude the existence of an absolute, non-empirical S. Since such an S does exist, though undetectably so, there is no problem in identifying the spatially distant events which are co-present with the here-now. To be sure, this identification cannot be executed in practice, as S must remain behind a principled veil of ignorance, but the possibility that it exists assures the presentist that there can be a privileged simultaneity relation and thus an objectively distinguished present. So if SR is interpreted as to only imply that there cannot exist an absolute S which can also be detected, but not to entail that there cannot be an absolute non-empirical S, then presentism remains compatible with SR and arguably with all of physics.
Bold by me.
Of course this strategy, which I think is the only feasible strategy in defense of presentism, reduces presentism to an article of faith, and certainly it has nothing to do with science. I should think most people would understand what desperate shape presentism is in vis-a-vis modern physics, if it is reduced to making untestable faith claims. But (I think) the above is what Sabine is driving at. And she may be right, if one accepts the above faith-based statement, that strictly Petkov is wrong
only in making a block universe a strict
entailment of SR, even though it certainly
supports the block model. You have made no arguments like this, and if you had, you would have been conceding that eternalism. is plausibly true, just not strictly entailed by SR. I would add that the philosopher Bradley Monton, a presentist whose work on time and other subjects I admire, also argues something like the above, but adds that he thinks a quantum theory of gravity superseding SR and GR might lay bare a preferred frame to vindicate presentism empirically and make it actually scientific. I believe I alluded to this earlier and, as I said then, I say now: we shall have to wait and see. I brought up Monton earlier with respect to my own residual qualms about eternalism.
By the way, Sabine is also a
quantum superdeterminist, which means she thinks that even if presentism is true, there is NO open future and NO free will. Presentism does not (necessarily) guarantee the free will that you crave, and eternalism does not (necessarily) preclude it, as I have taken pains to explain.