When discussing eternalism and the block universe, the concept of “now” always ends up getting relegated to an aspect of our consciousness, not something “out there”. “Now” seems to be the boundary between what we can remember and what we can only anticipate. But if, aside from entropy, the laws of physics are reversible and we live in a block universe, why are our memories only of the past? Matt O’Dowd gives an interesting answer.
O’Dowd’s answer (in case you skipped the video) is that correlations tend to increase over time, including the correlations in a physical object, such as a brain or rock, and its environment. Of course, in the case of brains, we call some of these correlations “memories”. Another name for many of these correlations might be “information”.
I’ve said before that I think information is essentially causation. And the vast majority of correlations come about by one correlated entity causing another, or by some common cause or set of causes in their shared history. So that fits.
O’Dowd does note the possibility of correlations existing without the causal processes, but they are highly improbable, akin to the probability of entropy decreasing on its own. And it’s worth noting, except in the simplest cases, correlations are only correlations due to connecting causal processes, both in their formation, and in whatever downstream effects the correlation may have, such as us recognizing a scar as the result of some kind of physical strike.
Ever since I found out that the measure of information content in Shannon information theory basically has the same mathematics as entropy, I’ve pondered what it meant. On the one hand, entropy itself is the result of causal processes. So both entropy and correlations seem to be the result of causal processes.
Of course, we do have correlations in our brain of future events, but they are either events we might cause, or see as probable due to some recognized repeating pattern. But these correlations have an uncertainty because of other correlations that don’t yet exist for unexpected events.
As I said above, it’s an interesting explanation. But I’m not yet entirely sure it isn’t tautological. We have memories (correlations) because they tend to increase over time. Still, not all tautologies are obvious, and so this still feels like an insight.
What do you think? Does the explanation work? Or is there a better one?