Originally posted by Locutus
Yes, but this is also true for space. If you remove all spatial dimensions, there is no existence either. If you remove one spatial dimension, things can still exist, but not if you remove all of them. The fact that the universe can't exist without its time dimension stems from the fact that time is one-dimensional. If there were multiple time dimensions, we could add/subtract them the same way we could add/subtract spatial dimensions.
No existence in our familiar form. That does not warrant idea that no existence is possible. Notice yourself, you can remove or add spatial dimensions freely, given that at least 1 remains, but as soon as you remove time, all spatial dimensions loose sense. Therefore time is more fundamental than spatial dimensions.
Besides spatial dimensions, you can imagine arbitrary number of any other dimensions, like imagine computer program - its in its own "space", in this case space is freedom of states, possibilities. And computing steps are interactions that can be assigned notion of particles or forces, and they exist in that computer time. Dimensionality of such computer can be made arbitrariliy large, and it has not even close resemblence to our spatial dimensions. When you stop that computer time, these particle cease to exist, and only single state remains. You can't think of all possible states as existing simultaneously, given constraints of computer program, there is only 1 way to proceed from given state - via causal interaction. And that's possible only when computer clock is restarted. And for particle inside computer program, there is no way to detect whether time runs or is stopped. The only thing what particle can detect is interaction _when_ time runs. For it, to exist is to have computer time running. Same for us, to exist _requires_ concept of time and interaction. For computer program, to jump in time means skipping series of cause/effect interactions and start interacting with something that doesn't exist yet or anymore. Not only does this scrap causality, it simply doesn't make sense.
Multiple time dimensions is as meaningless as multiple lengths. You can introduce as many as you like, it does not change essence of the concept, it remains unique.
Originally posted by Mentat
Possibilities exist, here and now, otherwise how could I be conceiving of them, here and now?
Possiblity: I imagine that I'm god and destroy that universe. Do you feel anything? Is that possibility "real"? Why is it not possible? Because we live in _real_ world? What makes it real? Constraints to possibilities? Okay, is there such a law of nature that forbids wimms to destroy universe? No, but there are laws of nature that states that to do that, you'd need to spend energy - interact. And they state that wimms has not even pion's chance in myuon's ass to kick the universe. Therefore we safely conclude, that this imagination is not real. But I conceive it, perfectly vividly. Its here, it exists! So what? It has no capacity to interact with real world. Therefore, it does not exist. There exist my braincells, that fired this way for duration of this post, they are real, but not the imagination. When I'm finished, horrible image of wimms destroying universe ceases to exist even in my imagination. And definitely its not something that could exist separately from my delusion.
See? To exist requires interaction. And interaction creates form. You might imply that now that I've written that delusion down, it exists on this forum in electronic shape. But its not what I imagined. What you perceive is delusion crap of somebody who'd better be drunk. And that's what it is - useless crap not end of world. But if you'd truly perceive sky crushing down on you, it would be real. Thing is what it appears to other thing to be.
There is a difference between imaginary delusions and real world out there. Imaginary delusions are limited by your own constraints only, real world limits you with requirement to interact in frame of laws we are trying to find out. As long as this universe is causal and logical, there is no room for "all possible universes", there is only one, here and now, constrained by only one possible direction of time - from past to future by means of cause/effect interactions.
To add here, consider abstract ideas, like geometric point, or line. Are they real? Do they exist? In our delusions, yes, but in universe out there - no, they don't exist. We can model world around us by using our imaginary shapes, but that doesn't make our imagination real, its merely description of something out there.
Time as coordinate dimension is of that kind - its is convenient to use it as spatial dimension, because this allows us to compute formulas, but it doesn't mean you can move on it the same way as you move in space.
As to multiple histories, they can't exist concurrently. To exist means to interact, if they don't interact they don't exist. You can shape the world around you, if you have free will, and this way decide which way your history develops, but there is no way you could swap your reality, much the same way as wimms cannot destroy universe, or how single value of variable in computer program cannot arbitrarily and acausally change whole state or even structure and program of the supercomputer. The only way how you could escape into other universe is via imagination. This is apparently perfectly possible, as we can learn from institutions with soft walls.
