Physics issues for a city where time flows in two directions

For the purposes of this question, lets assume that we are in Edwin Abbott Abbott's Flatland, but the world is a disk, with living shapes Above, and 'dead' shapes Below (the underside of the disk). However, time runs in the opposite direction Below, so if A. Square died on Monday, and went Below (let's assume there a 'strip of paper', like a passage, which he traverses to go from the top of the circular plane, to the underside), and was dead for five days, but was then allowed to return the the world of the living, he would arrive the Wednesday before he died.

I'm assuming that time is linear (no parallel universes), and that Cause and Effect operate, but not necessarily in that order. So, for example, A. Square might be able to warn his former living self of his impending death, but would do so knowing it will happen anyway (otherwise his ghost would not be there to give the warning in the first place).

The other assumption is that events unobserved by anyone are indeterminate (i.e. a kind of Copenhagen interpretation of time).

Can anyone see any logical issues with this? One concern is the travel via the 'strip of paper' connecting the top (Above) world with the Below world - would there be a point where A Square's ghost would be existing both in forward time, and backward time? Could this be done non fatally?

incidentally, time Below doesn't involve people walking backwards, and broken glasses reforming; locally, it appears as if time is moving forward, just backwards relative to those Above.

I've thought of one issue concerning computation: Imagine a machine which prints either the letter 'A' or 'B'. However, it is rigged to send this printout to its former self, and when the former self receives that printout, it is programmed to choose the opposite. So if it chooses 'A' it tells it's former self this, so it chooses'B', and visa versa. I'd imagine that such a weird 'paradox engine' would be in a suppositional state, like Schroedinger's cat in the box, until some highly improbable failure occurred to break it out of its loop (such as mechanical failure etc.) Would this mean there is a 'virtual' universe where the machine runs thousands of times before the improbable event occurs? I suspect this would mean our universe would occasionally have very improbable things happen due to such temporal feedback loops occurring in nature...

The motivation for this is a fantasy story, where I'm trying to devise a mechanism for prophecy based on (as in much folklore) the notion of time working differently in 'fairyland'.

posted almost 9 years ago

Mobeus‭

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