> It also sidesteps another important distinction: why the past is the direction we can form memories of.

That much is very well understood.

Order from the past is what we harness to make memories. That’s why you can’t have memories the other direction.

Think of a computer. It takes ordered energy, organized as a stream of electrons, which end up in a less energetic form we can’t use and heat we can’t use.

But in the eddies of that entropy, the computer calculates a few things. Uses up that order to store a few things.

The net is massive loss of order. One electron can go either way on a wire. With (usually) or against (mostly) voltage. (Because we randomly decided electrons are negative.)

But a trillion electrons statistically can only go one way.

The order we build in our minds and computers is a fraction of the order from the past. Which is just saying, we get order from the direction there was more order.

You could set up a tiny few particle experiment, shield it from interactions, and operations can randomly go either direction.

But our neurons and brains are built out of countless particles. We can only do ordered things with them by consuming order from the direction there was order.

A windmill can do work, but only if you let higher water push the wheel. If the river stops from above, no amount of water below is going to power it. Statistically to the level of certainty.

The order in the universes origin, statistically cascades away in all directions. And all those directions, radiating from order, away from order, are what lets us think, store memories, and have an experience we call time.

But with a constant total net loss of order. We are just those eddies that defy the rivers flow, but only fractionally, by harnessing the rivers flow.

(For how there can be places where order “first” appears, see my other comment. Unlike this one, it is highly conjectural.)

Yes exactly! (Great answer!)

And this is why when the universe has a temporal entropy gradient, the direction of decreasing entropy gets labeled "the past". It's not because the past is the direction of "-t", but because the past is the direction of "-dS/dt". Otherwise we wouldn't form memories of it.

This dissolves the mystery of why the past has lower entropy than the future despite the laws of physics being time-reversible, and replaces it with the question "why does the universe have an entropy gradient at all?"

Thanks, you said it better. The derivative makes it clear! The direction of maximum entropy decrease in our 4D topology, gets labeled “-t”. The direction of maximum increase “+t”.

Did you read my other sibling comment about ordered regions of reality being inevitable?

(Not being snarky, just that was the question I have a conjectural answer too.)

Yes, I'm not entirely sure I have a concrete idea of what you mean, so I can only interpret it vaguely. But I think it is a fair hypothesis.

It reminds me of Feynman's QED, where he explains how a photon can take every path to its destination, and the end result looks almost like it's taking just one path, because all the other paths end up with scrambled phases that cancel each other out when you sum them up.