Entropy and Memory

It’s overwhelmingly probable that all of your memories are false.

Consider:

Entropy is a measure of the disorder of a system. The higher the entropy, the higher the disorder.

If a deck of cards is ordered by suit and then within each suit by ascending rank, then that’s a low entropy state. This is because out of the 8.06 * 10 to the 67th (52!) possible unique arrangements of the cards in a standard 52 card deck, there’s only 24 that fit that particular description.

A “random looking” arrangement of the deck is a high entropy state, because there are trillions of unique arrangements of a standard 52 card deck that will fit the description of looking “randomly shuffled”.

Same with the egg. There are (relatively) few ways to arrange the molecules of an egg that will result in it looking unbroken, compared to the huge number of ways that will result in it looking broken. SO, unbroken egg…low entropy. Broken egg…high entropy.

AND the same with the universe…there are (again, relatively) few ways to arrange the atoms of the universe in a way that makes it resemble what we see with people and trees and planets and stars and galaxies, compared with the gargantuan number of ways to arrange things so that it resembles a generic looking cloud of dust.

OKAY. Now.

Of the relatively few ways that the elementary particles of the universe can be arranged so as to resemble what we see around us today, only a tiny fraction of those particle arrangements will have values for momentum and position that are consistent with them having arrived at that state 13.7 billion years after something like the Big Bang.

The vast majority of the particle arrangements that macroscopically resemble the world around us will *instead* have particles in states (e.g., with positions and velocities) that are consistent with the particles having previously been in something more like a giant dust cloud.

By which I mean: If we take their current positions and velocities, and work backwards to see where they came from, and go back far enough in time, eventually we will not arrive at the Big Bang. Instead we will arrive at a state resembling a giant dust cloud (probably a very thin, spread-out dust cloud).

SO, bottom line:

Out of all the possible configurations that the universe could be in, ones that have people, and planets, and stars, and galaxies are extremely rare.

Further, even if we then only consider those extremely rare possible configurations that have people, and planets, and stars, and galaxies – the ones with particles in states (e.g., with positions and velocities) that are consistent with having arrived at this configuration 13.7 billion years after something like the Big Bang are STILL rare.

We don’t know the exact state of our universe’s particles, but in statistical mechanics the Principle of Indifference requires us to consider all possible microscopic states that are consistent with our current macroscopic state equally likely.

So given all of the above, and our current knowledge of the laws of physics, the most likely explanation is that all of your current memories are false and that yesterday the universe was in a HIGHER state of entropy, not a lower state (as would be required by any variation of the Big Bang theory).

Physical systems with low states of entropy are very rare, by definition. So it’s very improbable (but not impossible) that the unlikely low entropy state of the universe of today is the result of having evolved from an EVEN MORE UNLIKELY lower entropy universe that existed yesterday.

Instead, statistically it’s overwhelmingly more probable that the unlikely low entropy state of the universe today is the result of a random fluctuation from a HIGHER entropy universe that existed yesterday.

And thus your memories of a lower entropy yesterday are most likely due to this random fluctuation, not due to yesterday actually having had a lower entropy than today.

[Based on my reading of Sean Carroll's book "From Eternity to Here"]