The single time machine

I have pointed out in the past that if time machines are ever going to be invented, we should have already seen them, since presumably people would be traveling back to our time. (But maybe there is some pact on the part of their possessors to keep there existence secret.)

But there is one time machine. It is called the physical universe, and it continually transports us forward in time.

8 comments:

  1. "if time machines are ever going to be invented, we should have already seen them, since presumably people would be traveling back to our time."

    This presumes that time machines have sufficient range to travel to our time.

    According to the theories of Ron Mallet, the time machine would only be able to take people back to the point in time when it became operational.

    The time machine in the film 'PRIMER' works along these lines. I believe the time machine in the film 'Time Crimes' could only take you one hour into the past. It's a fun movie that explores the paradoxes of time travel.

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    1. "According to the theories of Ron Mallet, the time machine would only be able to take people back to the point in time when it became operational."

      That seems a little ad hoc. But then I don't know the theories of Ron Mallet.

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    2. Post hoc ergo imprompter hoc?

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  2. There is an interesting further philosophical point here: the very notion that time travel is even possible depends on some version of the Eternalist view of time (that is, the past, present and future are all equally real: the whole present, past, and future of the universe already exists in a massive “block”).

    But Eternalism is not proven, it remains a kind of lazy assumption from general relativity and is deeply incompatible with the way we consciously experience a dynamic moving present.

    And actually some highly respected physicists now argue that Eternalism is wrong and they argue that Presentism (i.e., only the present really exists) is right.

    I discussed this issue here for what it is worth:

    http://socialdemocracy21stcentury.blogspot.com/2013/04/the-nature-of-time-science-and-economics.html

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    1. this goes back to the "the map is not the terrain". The manifold in GR is indeed an object that is just there. But it's the map, isn't it?

      Anyway Gene I find your proof compelling but you might not know about Feynman's notion of one particle going back and forth in time, weaving the universe. Worth hunting down if you don't.

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    2. Ken, I know about Feynman. This I think supports my contention: we have already seen that particle, right?

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  3. Indeed! Good point.

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