If we accept that our perception of the world and the actual objective truth of the world in itself are disjoint - that we cannot know certain (or perhaps any) truths about the world - then we essentially are living life as an observer "watching a movie."

Ignoring the concepts of determinism and free will for now, we could imagine that (working with the idea that existence is "experiencing a series of moving pictures") we are watching the movie backwards. If you take a worldview with certain truths - gravity pulls two entities together - and negate all of them (Of course, it may be that not every "truth" can be negated, but I'm not sure if that matters) you arrive at the same worldview, right? Just from a different perspective.

Finally, my question:

If gravity pushes rather than pulls, and like magnets pull, and opposite magnets push, etc - reversing the causal arrow for every fundamental force of the universe - is it the same world?

  • Gravity up involves few(one?) moments on the ground and many morents in the air, but gravity down involves few moments on the air and many on the ground. For human POV gravity being at the limit of it's movement capacity in one directon would make this not work, no? – StarWeaver Jun 14 '17 at 23:00
  • I'm not sure. Static equilibrium would involve the normal force pulling downwards and gravity pushing upwards (for a human on the surface of Earth). It's my (limited) understanding that the normal force is an abstraction upon molecular forces, so reversing all of them too should be fine? – Kevin Connors Jun 14 '17 at 23:58
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    If we accept that our perception of the world and the actual objective truth of the world in itself are disjoint we have no reason to believe that our notions even apply to the actual objective world. In other words, it makes little sense to say that it "really" is like the movie backwards, or that it can be described by our words at all. This is Kant's lesson. If the only difference is in the reversed direction of time it is not a "real" difference at all, we just have two equivalent descriptions of the same "reality". What objective meaning can it have that the time "really" moves backwards? – Conifold Jun 15 '17 at 19:43
  • I'm voting to close this question as off-topic because it hinges on the use/mention distinction between "forward" and forward. (= time is moving forward because that's what "forward" means; if you want to spell it "backwards", then it's still moving forwards but now using a different spelling). – virmaior Jun 19 '17 at 12:34
  • @Conifold - in terms of perception, I don't think it matters. If time is reversible, which I guess is what I really wanted to know, then maybe it's possible to reverse time. virmaior I suppose my real question (what I was wondering, not what I asked) is: is time reversible? And I think jobermark answered it well. – Kevin Connors Jun 21 '17 at 15:12

Physicists have actually considered this question. Some would say no, due to the symmetry of our physics The law that requires an increase in entropy over time is the only place our accepted physics loses its reversibility. And it is basically taken as an axiom.

But theories about tachyons and antimatter suggest it may be possible to accumulate information and even have configurations of matter travelling in the opposite direction (or at any angle relative to our notion of forward) in time. Richard Feynman pointed out that these are not daft imaginings, and made the point by suggesting that all the electrons and positrons in the universe could be a single entity, which has simply reversed trajectory in time, charge and or 'spin' many, many times, as far as our current physics can tell.

If these make sense, our linkage of entropy to information may only be an observation, and not a fact. The observation would be what we see only because our memory is an exothermic chemical process. An 'endothermic' being is conceivable.

If the universe is already continuously going both ways, then forward or backward it is the same world. But if tachyons and antimatter are deeply intertwined, different aspects of it may never be able interact.

So the next step: If time goes both ways, is there some other direction relative to which it actually reverses?

Hawking has suggested that time should be measured as a complex number. This would mean that it has two dimensions, to a limited degree (the real and the imaginary axes). Then real time would be able to reverse relative to the imaginary time axis, explaining how time can be a continuous function and still begin. What would an extra dimension of time look like?

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