Paradoxical?

88 mph?

The classic time travel paradox is to wonder what would happen if you traveled back in time and killed your grandfather before your father was conceived.

1. Your father would never be born so…
2. You would never be born so…
3. You couldn't travel back in time so…
4. Your grandfather would survive so…
5. Your father  would be born so…
6. You would be born so…
7. You could go back in time to kill your grandfather
8. Start again from #1

This particular 'causal' paradox has being causing time travel authors problems for years. It's been used as proof that time travel is impossible and that if it were possible something would interfere to prevent the murder or whatever event is a problem.

Any change you make in the past impacts the future in some way. Even a tiny change can trigger a major event later. Years ago I read a story about a time traveler who stepped off his allowed path and trod on a butterfly in the age of dinosaurs. When he returned to the present everything had changed. Humans no longer were the dominant species on earth. Presumably:

• the butterfly did not lay eggs
• the eggs did not hatch
• the caterpillars did not feed a shrew like mammal which died of hunger
• evolution did not as a result eventually produce apes and mankind. 

So if time travel was to be found possible would it be considered too dangerous to use?
A while back I wrote a short story in which the time travelers had to go back in time to make sure that the Titanic did sink (See It Wasn't a Dark and Stormy Night - Titanic Time) If it didn't sink billions would die as a result. 1,500 deaths in the Titanic disaster was a small price to pay to save billions.

Is there a way around these paradoxes? Yes there is!

At every instant in time where alternate events can occur other alternate universes are created and branch off. As soon as you make a change through time travel you close down one possible alternate universe. Go back and kill your grandfather and your universe no longer exists. As a result you can never return to it but you could go forward in time to any of the myriads of universes where you didn't commit the murder. There would be a slight problem though. Since you didn't come from that universe there would now be two of you! One of me in the universe is enough! Perhaps if I time traveled I would be best returning to the universe where I did kill my grandfather. I wouldn't be around there. The only problem with that is I arrive with no identity. A person with no history, no possessions other than what I take, nowhere to live. Effectively I'm an undocumented alien in that world.

So if I do decide to take up time travel I'm not going to travel far in the past. I'm not going to do anything which puts me at risk. Perhaps I'll travel back in time a couple of hours and give myself the winning lottery numbers? I suspect anyone who can time travel is well aware of the risk which is why we don't see travelers from the future.

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