# Artifacts that exist only and because of time loops

**URL:** <https://boards.straightdope.com/t/artifacts-that-exist-only-and-because-of-time-loops/268758>\
**Category:** Factual Questions\
**Created:** [October 12, 2004, 2:26am UTC](https://boards.straightdope.com/t/artifacts-that-exist-only-and-because-of-time-loops/268758 "2004-10-12T02:26:45Z")\
**Posts on this page:** 2\
**Page:** 4

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**Author:** ![ntcrawler](https://avatars.discourse-cdn.com/v4/letter/n/34f0e0/32.png) [@ntcrawler](https://boards.straightdope.com/u/ntcrawler)\
**Post date:** [October 13, 2004, 10:40pm UTC](https://boards.straightdope.com/t/artifacts-that-exist-only-and-because-of-time-loops/268758/61 "2004-10-13T22:40:06Z")

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If, for the sake of discussion, creation of the time machine takes an hour, and travel in the machine is instantaneous, then when I am first given the slide rule it is an hour old. But if it is an hour old and I have it for another hour before giving it to my past self, it is 2 hours old. But if it is 2 hours old and I have it for another hour before giving it to myself, it is 3 hours old. Ad infinitum.

Am I missing something?  
[/QUOTE]

Only if you keep giving yourself the same slide rule, or watch, or artifact, or piece of paper. there is a simple way out of this:

I am sitting here now at my desk. Suddenly, NtCrawler from 2005 appears to me and gives me a watch. So far, in this thread people assumed that I would keep that watch around, wait until 2005, in order to go back in time and give it to myself. But that would make it a djinn. So a simple way to prevent that:

I keep that watch. But before my scheduled depature back in time in 2005, I go out shopping, buy the exact same watch that I already have, and THAT’s the watch I use to give to myself. So it’s still one watch, with a definite beginning, and a traceable timeline. It’s simply a year older when time passes past my departure in 2005. Am I right?

And what would happen if I gave myself the WRONG watch? Well, using Douglas Adams and his Hithhiker writings as a guide, I suppose the universe would implode and recreate itself into something even stranger than before 😃

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [October 13, 2004, 10:57pm UTC](https://boards.straightdope.com/t/artifacts-that-exist-only-and-because-of-time-loops/268758/62 "2004-10-13T22:57:09Z")

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Addressing both the infinite-age argument and the random-object argument, the best SF writers generally include some form of copying and possibly reinforcement of their djinni. For example, in the afore-mentioned “By His Own Bootstraps”, the hero finds a notebook with a primer on the local language written in it. Using this notebook, he learns the language, and goes on to converse with the locals. Eventually, the notebook starts getting a bit dogeared, so he transcribes it into a new one, a task made easier by his now familiarity with the language. Of course, that transcription ends up being the original notebook.

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