When I was younger I imagined in my head that a specific moment in time is literally just all of the information about the observable universe -- the position,

When I was younger I imagined in my head that a specific moment in time is literally just all of the information about the observable universe -- the position, momentum, temperature, etc of all of the particles in existence relative to one another. I’m running on very little sleep right now so be prepared for a little woo here; I’m expecting someone smarter to come correct some misconceptions in my take and hoping to learn a little bit from that. For me, that idea always been enough to get by (without existential questions), albeit it's a little bit different from the three-axis-plus-time description in the article. It explains really intuitively why reverse time travel isn't possible (non-reversible reactions, energy required to reverse the entire universe into a previous state, etc). It also makes it intuitive that time does exist, since "time" is a noun referring to the overall state of the universe - a specific state in a set of states that at least appears to progress sequentially... but perhaps does not. Actually, looking at the questions in the article, it seems to jump out that time is uncountably infinite (since "absolute time" cannot exist). Even so, the “arrow” of time would be evident from within any of these states because there is only one direction that certain starting conditions can lead. “Time” does not account for parts of the universe in isolation, but rather all of it as a whole - so there are always plenty of pointers. Edit: This seems to be a naive/flawed way of understanding canjobear's statement: > Time is the direction in which entropy always increases. It's the most real thing there is. I want to rephrase to, "if time doesn't exist, how do we know where things are?" or "if time doesn't exist, how do things move?" - which seem to get back to the 3-axes-plus-time description.