Round Trip Paradox

[Cosmo]

A time-travel paradox from Robin Le Poidevin’s Travels in Four Dimensions:

Tim is spending the summer holiday at his grandfather’s house in rural Sussex. Bored one day, he wanders into his grandfather’s library. On one of the more remote shelves, Tim discovers a dusty book with no title on its spine. Opening it, he sees it is a diary, written in a familiar hand. With a growing sense of wonder he realizes that one of the entries provides detailed instructions on how to build a time machine. Over the next few years, following the instructions to the last detail, Tim builds such a machine. It is finally completed, and he steps on board, and throws the switch. Instantly, he is transported back fifty years. Unfortunately, both the machine and book are destroyed in the process. Tim writes down everything he can remember in a diary. He cannot rebuild the machine, however, because it requires technology that is not yet available. Reconciled to getting back to the twenty-first century by the traditional method of doing nothing and letting time carry one back, he marries and has a daughter. The family move to a rambling mansion in rural Sussex. The diary is left to gather dust in the library. Years later, Tim’s grandson, spending his summer holidays with his grandfather, discovers the diary.

Where did the information on how to build a time machine come from? From the diary, of course, which itself was written by Tim. But where did he get the information from? From the very same diary! So the information has appeared from nowhere. At no stage has someone worked out for themselves how to build a time machine and passed on the information…

[Einstein]

I don’t think anyone has ever figured out a proof for that. But it’s my guess that quite possibly a perpetual motion machine may work this way. Energy generation may be a free byproduct based on this principle.

[seivtcho]

We may suppose, that he invented the time machine firstly, went 50 years back, lost the machine and the way back to his time, and this is why he wrote the book and placed it deliberately on a place, where he will find it after 50 years. The movie simply starts with the second him, finding the book.

[Gpa]

That’s the bootstrap paradox. It has been discussed here before.

https://timetravelinstitute.com/t/blast-from-the-past/11183

[RainmanTime]

But it’s my guess that quite possibly a perpetual motion machine may work this way. Energy generation may be a free byproduct based on this principle.

As you so often point out about what others share: You are talking about fantasy. There is exactly zero evidence that such things exist, much less that they are possible given what we know about the laws of energy.
RMT