Re: TimeTravel

Brian D Williams (
Fri, 23 Oct 1998 12:48:09 -0700 (PDT)

fom: Hal Finney <>

Brian D Williams, <>, writes:
>> You are arguing that because no one has come back from the
>>future that it proves time travel (backward) is impossible. I
>>merely stated the obvious, the reason no one has come back from
>>the future isn't that time travel (backward) is impossible
>>(although I believe it is.) it's that the future hasn't happened

>I don't quite understand how this argument works.

>Suppose we wait until the future happens (so to speak!), and
>someone invents a time machine that allows travel into the past.
>I gather that you think that is at least logically possible.

I do not think it is, or will be possible, to travel backwards in time. You can be logically correct, but dead wrong. but lets play this out anyway.

>Now we travel into the past, back to good old 1998, and here we
>meet Brian D Williams. We introduce ourselves to him and say that
>we are from the future and that we've come back in a time machine
>to visit him.

>He says that is impossible, because the future hasn't happened
>yet, and shows us his message which he had just sent off to the
>extropians list.

>Obviously he is wrong in some sense, because he concluded that
>time travel was impossible, yet it was possible, and we are there.
>What is wrong with his argument?

I wouldn't be easy to convince, but we were arguing something different. Dan's postulate (if I understood him) was that since no visitor has returned from the future this proves time travel is impossible. I guess to make it clearer there are at least two possibilities. 1) time travel (backward) is impossible 2) The future isn't here yet. So the lack of the visitor doesn't prove 1 because 2 is also possible.

Now to answer your question, If our future visitor arrived and was successful in convincing me (I'd need a ride to prove it, well two rides) then I would be flat out wrong, and we would not be living in the present except from our perspective.

We would literally be history.

But as I stated I do not believe this is possible.

But it is fun to think about (another Lewis Carroll reference ;) )

Member,Extropy Institute