Rick asked:

I was reading Stephen Hawking's book, A Brief History of Time,as there was something in it that had
me in a fog for a week. Mr. Philosopher, please, could you tell me about the existence of time travel?

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It seems to me that there is one very strong argument against time travel. It is that if there were such
a thing we would have had tourists both from the past and from the future by this time. But we know
of no such tourists. So, it seems to me that time travel is unlikely.

Kenneth Stern