I didn't even bother to read this article. It looked scary. But I think you might like it MJ.
http://www.technologyreview.com/blog/arxiv/25494/
It claims to do away with the Grandfather Paradox.
Time Travel Link 2
(4 posts) (3 voices)-
Thanks. I still think this sort of solution runs afoul of the problem I address in Mass Suicide and the Grandfather Paradox, viz., that something must have intelligence to know what events must be avoided and which can be permitted. The essence of the new form is that certain events become unlikely to the point of impossible because of causal chains, but probability of outcome somehow then ceases to be based on simply laws of physics. That is, suddenly the probability that the bullet I fire from the sniper rifle will hit my grandfather drops from the 95% that is based on my experience and equipment and the conditions to effectively 0% because of the necessity to avoid a paradox, which means that the universe must know what a paradox is and what events will cause one.
I don't buy it. Making the universe God does not solve the problem.
--M. J. Young
Tue Jul 27 2010 1:35 am # -
Max
Membersomething must have intelligence to know what events must be avoided and which can be permitted.
That probably means that the time machine have post selection algorithm that can allow or deny something from traveling to the past. That time machine must have the ability similar to Paul Atreides "Know Future" or something.
Tue Jul 27 2010 2:26 pm # -
Max, you're putting the solution in the time machine; that means that it's not a principle of time itself but a safety created by the machine's designer.
It also doesn't get you out of the difficulty because of "natural" time machines. That is, if we allow that it is possible for there to be a naturally-occurring wormhole with temporally desynchronized ends, someone entering the future end would exit from the past end, and then could take such actions as might cause a paradox (e.g., destroy the wormhole, kill his younger self). Since the wormhole is presumed to be a natural phenomenon, we must then either conclude that it was not intelligently designed and therefore has no such intelligent algorithm or that all things are intelligently designed and thus there is divine control over the events of our world. I am not uncomfortable with the latter view, but I think that if we are saying "God would not allow it" then
- We'd better by very good theologians certain of what God will and will not permit, and
- We must not then also pretend that there is no God or God is irrelevant to events in life.
Further, excluding natural phenomena, what you've said in essence is that the people who built the time machine included within it a paradox-preventing system. That would be very wise of them, and also very smart of them, since it's not at all clear how such a system could possibly work. However, it puts the onus for preventing paradox on the designers of the machine. The argument of the article (and similar articles) is that the universe itself prevents paradox, and that therefore there are intelligent algorithms and precognitive abilities inherent in "Nature" which work to protect history. That makes "Nature" intelligent and omniscient, and so we have replaced God with a different name and made ourselves feel safe by having all the benefits of God with none of the concurrent obligations.
More simply, if the machine has a post selection algorithm, the designer incorporated it into the design; what prevents someone from building a similar machine without that algorithm, and what happens if the algorithm fails to recognize a potential paradoxical situation? If we are relying on human intelligence to prevent paradox, eventually it will fail us.
--M. J. Young
Tue Jul 27 2010 6:12 pm #
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