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From: bl@hplabsb.UUCP (Bruce T. Lowerre)
Newsgroups: net.physics,net.sci
Subject: Re: A Sane Man Proposes A Time Travel Experiment
Message-ID: <3657@hplabsb.UUCP>
Date: Thu, 14-Aug-86 12:34:40 EDT
Article-I.D.: hplabsb.3657
Posted: Thu Aug 14 12:34:40 1986
Date-Received: Thu, 14-Aug-86 21:51:36 EDT
References: <289@axiom.UUCP> <5723@lanl.ARPA> <7489@tekecs.UUCP> <83@unc.unc.UUCP> <20093@rochester.ARPA>
Organization: Hewlett-Packard Laboratories
Lines: 23
Summary: The time paradox - two answers
Xref: mnetor net.physics:2657 net.sci:1194

In article <20093@rochester.ARPA>, ray@rochester.ARPA (Ray Frank) writes:
> 
> This has probably been discussed before so forgive me if it is a rehash of
> an old paradox:
> 
> If a man goes back in time and starts a chain of events that gets him killed
> off before the time from which he left, then he would not have been alive at
> that future time to go back in time to get himself killed off, thus if he was 
> not alive to go back in time, he could not have been back there to get himself 
> killed off which means that he would be alive to go back in time......screw it.
> Assuming time travel could be possible someday, how do you solve this paradox?

A cute answer given by Douglas Adams in _Hitchhiker's Guide to the Galaxy_ is
that all events in time, past, present and future, are interrelated and fit
together.  That is, your question is meaningless because since you are alive
in the, present then you did nothing in the past (during your time travels)
to change that fact.  And, in fact, anything you did do in the past was
necessary for the future (and present) to be the way it is (or will be).

My own feeling which I believe is the correct answer, is that we can observe
the past events all we want with as much detail desired but we can make NO
change to those events.  Time travelers (to the past) will be in another
dimension, if you will, and cannot make direct "contact".