
The Secret Life of Time - sergeant3
http://www.newyorker.com/magazine/2016/12/19/the-secret-life-of-time
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empath75
It might be interesting to consider how and whether time is relevant to
computation. For example-- does time have an arrow on a computer?

It does, for at least two reasons: 1) Computation physically produces heat and
increases entropy. 2) Many operations lose information -- for example XOR's
can't be run backwards to reproduce the original inputs.

People have tried to tackle both issues with reversible computing.
[https://en.wikipedia.org/wiki/Reversible_computing](https://en.wikipedia.org/wiki/Reversible_computing)

Someone even wrote a programming language that was (logically) time-
reversible:

[https://en.wikipedia.org/wiki/Janus_(time-
reversible_computi...](https://en.wikipedia.org/wiki/Janus_\(time-
reversible_computing_programming_language\))

~~~
azeirah
Does having a time-reversible programming language mean that if you start with
the output of a given program, you can run the program backwards and get the
input?

This would be useful outside of research. Though, I expect the memory usage
will be ridiculous.

~~~
conistonwater
Isn't that already a thing, if you really want it? [1,2,3]

[1]
[https://en.wikipedia.org/wiki/Retroactive_data_structures](https://en.wikipedia.org/wiki/Retroactive_data_structures)

[2]
[https://www.youtube.com/watch?v=T0yzrZL1py0](https://www.youtube.com/watch?v=T0yzrZL1py0)

[3]
[https://www.youtube.com/watch?v=WqCWghETNDc](https://www.youtube.com/watch?v=WqCWghETNDc)

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gloriousduke
Still working through the article, but it reminded me of the presumable fact
that everything that happened before the first conscious entity existed in the
Universe was essentially instantaneous. Same goes for time's forward
direction. Without consciousness, i.e. with a perfect form of stasis, one
could time travel to just before the heat death of the Universe in an instant.

John Archibald Wheeler took this idea even further with the PAP, the
Participatory Anthropic Principle.

~~~
eternalban
You are asserting that "the Universe" can exist without a "conscious entity".

~~~
dboreham
A Whale, of course.

~~~
eternalban
Or a potted plant.

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lisper
The passage of time is an emergent property of quantum entanglement. Yes, I
know that sounds like new-age hooey, but it's actually based on solid science:

[http://blog.rongarret.info/2014/10/parallel-universes-and-
ar...](http://blog.rongarret.info/2014/10/parallel-universes-and-arrow-of-
time.html)

[UPDATE] I would really appreciate if those of you who are downvoting this
comment would tell me why.

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sjbase
“Where is it, this present? It has melted in our grasp, fled ere we could
touch it, gone in the instant of becoming.”

It might be a stretch, but this seems like a small glimpse of the concept of a
time differential ('dt'), a thousand years before the math existed to describe
it explicitly.

~~~
Retra
Most ideas don't have explicit mathematical descriptions. Why would this one
be more notable than any other?

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krzrak
Fascinating article. Great, long read.

