Philosophical Sketch: Shrinking Future Time

I’ve mentioned Shrinking Future Time (SFT) before, and according to the Internet Encyclopedia of Philosophy, it isn’t one of the three theories on the ontological differences (or lack thereof) between the past, present, and future. As the name suggests, the theory is just turning Growing Past Time (GPT) on its head: the present and future are real, but the past is not.

My goal here is just to start setting up a motivation for further inquiry. Why think SFT is even plausible? Thus I’ll mostly be appealing to some intuitions to try to draw out the possibility.

Presentism has the appeal of, well, right now is all we can seem to access right now. The past is gone and the future isn’t here yet. Dinosaurs don’t exist, and neither do teleporters. GPT adds the past, while still acknowledging the present is special. The past did happen, after all, so saying dinosaurs aren’t real seems kinda silly. But the future is still left undetermined. The present is special as it’s the edge of the block. Eternalism is different from these two both in the reality of the future as well as the present not being objectively special. Subjectively, sure, I’m now, but I’m also here, and we don’t think here is more special than there besides that we’re here. So likewise tomorrow and yesterday are no different than now; I just happen to be now.

SFT clearly shares some elements of each of these, and comparing to space continues to be intuitively useful. In space, there are some places that are, and some places that are not. If we embrace presentism, a place can be and then not be. Or not be and then be. (If we embrace eternalism, it can be only at certain times.) Twenty years ago, if I asked you to go to Blockbuster and pick up a tape, I’d be making a coherent request because Blockbuster was indeed a place. If I ask now, I’m asking nonsense because there is no such place.

Regardless of whether it’s 2017 or 1997, here is always a place, assuming anywhere is, and Narnia is not. (It’s at least not real.) Now one may object already with the Blockbuster example by saying that all that’s changed is the name and maybe some local geography, but the absolute location in space is still there. There’s a patch of ground there that was there twenty years ago and whether the building on top is a Blockbuster or a Burger King doesn’t make an ontological difference here. So consider instead first Narnia. It’s not a real place, so a request to fetch something from Narnia is an impossibility at best. If the universe (i.e. the totality of all space) itself is changing size, then absolute locations (if there are such things) may exist and then not or not and then do.

What Blockbuster helps illustrate is an idea of accessibility. Blockbuster being there basically means it is in some sense accessible. Of course, we also want to say Neptune is a place, but as it stands, nobody can get there from here. However, there’s no deep (meta)physical restriction in the way like there is with places that just don’t exist, only a lack of technology. Presumably the ontology of time and space is not reliant on human technology. (Well, I think it probably is, but not in a way that seems to affect the plausibility of SFT.)

Let’s return to time. Like I can get from here to there, I can get from now to later. The restriction on the “there” is just that the place has to be real. If we continue the analogue, then the restriction on getting to another time is that the other time has to be real. The inverse also applies: if I can’t get somewhere, it’s because it’s not real (again, using this broad definition of “can”), and likewise if I can’t get to some time, it’s because it’s not real. Thus we have the accessible, thus real, present and future and the inaccessible, thus unreal, past. Thus, SFT.

An obvious presentist objection is that we can’t actually get to the future because we’re always in the present. Of course, by that reasoning we can never get there because we’re always here. What we have in motion through time would thus be akin to moving through space but obliterating every location as soon as you leave it. This seems to not be the case for space, but it looks like it could fit for time.

In sum:

  • The present obviously exists.
  • The future must exist for us to be able to get there.
  • The past not existing explains why we cannot go back.
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WP: Time Freezing feat. Naps

Today I have another writing prompt to respond to with philosophy instead of fiction. This time it’s about time. (Conveniently, time is another one of my favorite topics.)  Once again it originates from tumblr.

 

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Time travel is a surprisingly well-explored area in philosophy. Freezing time is similar to time travel in some ways, though I’ve yet to come across any papers involving time freezing. (A few quick searches on PhilPapers and in Susan Schneider’s Science Fiction and Philosophy didn’t yield anything, either.) So, here I will consider how time freezing would work given a variety of theories of time.

Theories of Time

There are two main questions to answer regarding how time operates, at least as far as time freezing is concerned:

  • Is the present special?
  • Do the past or future exist?

If the present is not special, the latter question is irrelevant. We have the B-series of time wherein all times are equal and “now” is just an indexical. That is, “Rick and Morty is on TV right now” just means “Rick and Morty is on the TV at 15:41 on 2017-06-29″. This is similar to how we don’t usually think of here as being special. I’m sitting here, but this chair is no more existing than any other chair.

If the present is special, then the existence of the past and future can be brought into question. If they both do, we have the full timeline already existing, but there’s a sort of “moving spotlight” going along the line, wherever that spotlight is being “now”.

The other extreme is presentism: there is only now. If we add the past we get the “growing block” theory wherein that which already has happened is still existing or real, but the future is still unwritten. The other option, wherein the future already exists but we burn the past behind us, is at least conceivable, though I’ve never heard of anyone thinking it’s true. Since it could make for interesting writing, I’ll consider it.

Freezing Time

So, let’s consider each of these theories and how freezing time would work. By “freezing time” there’s two possibilities. One is that time itself stops, but the freezer is able to move about. The other is that everything besides the freezer just stops moving. The latter is at least conceivable under any of the theories. The trickier bit is making time itself stop.

With the B-theory, time is just the sequence of everything that happens. Thus freezing time would be nothing more than many actions fitting into one simultaneous event. Now, for naps this might not be too bad. Naps already take no perceived time, so the napper would merely be energized all at once rather than with chances for interruption. Since time does not actually move with the B-theory, there’s really nothing to freeze. Since time is static in the first place, you can’t make it more static.

Presentism on the other hand has no time other than now, so to make now last longer has to mean something else. (Under any dynamic theory it is always now, but presentism adds the extra challenge of leaving nowhere to stall a spotlight or keep the cube the same size.) As far as I know, the best way to put time is as the changing of objects. This would mean there really is also nothing especially temporal to freeze. All objects would quit changing, less the ones the freezer interacts with, and this is all there would be to time being frozen. As far as a nap goes, since perceptions while napping do not change, napping is already effectively freezing time, just with a jump at the end.

The moving spotlight offers a nicer example of time actually staying still. While the freezer moving about would be tricky to explain without appeal to other things not, it may instead be explained as the freezer being able to move while the spotlight stays still. The trickier bit for this and the next two theories is that the spotlight staying still (and being able to change as it does) is that it brings in a sort of hypertime. Time may move at one second per hypersecond, and then some power enables you to maintain your hypervelocities (length per hypertime) even as velocity (length per time) becomes undefined because no time passes as you move. (The trickiness with hypertime is that if there’s hypertime, why not hyperhypertime, hyperhyperhypertime, etc. In fact, a whole arms race could be made of this! Alice can freeze time, but then Bella can freeze hypertime. And then Carly can freeze hyperhypertime. With the right odd affinity for dimensional analysis, I’m sure this could be used for a unique plot.)

Naps would be less interesting here. You’d get a bit of extra rest by only using hypertime while time waits. That you continue to age would mean your lifespan would be shorter by some hours but the same length in hyperhours. (Or experienced hours, except for that you threw those away with that nap!)

Growing block and shrinking block (the handy name I’m giving to the present and future existing) operate in more or less the same way. Growing block is, for these purposes, moving spotlight with the future undetermined. That doesn’t really affect freezing time. Likewise, shrinking block is moving spotlight without a real past. (Admittedly, I don’t know what the payoff of that is. Maybe there is one, but usually the payoff of no past is nothing to determine the present. But since the future is already set, you don’t really get radical freedom.)