3 things we call “Time”
Confusion about the reality of time comes from the fact that there are three entirely different things that we call “time.”
Dimension of Time
Spacetime is a four-dimensional manifold in which an observer perceives three dimensions as “space” and one as “time.” All four spacetime dimensions can be either fundamental or emergent from some fundamental phenomena (we don’t know for certain). Still, we know the exact direction in the four-dimensional manifold of what each observer perceives as “time” depends on that observer’s velocity and gravity in the vicinity. So, we are confident that the Dimension of Time is as real as the other three Dimensions of Space.
Arrow of Time
All the dimensions of space are isotropic, meaning that the laws of physics are the same in all possible directions in space. Dimension of Time, on the other hand, is anisotropic, meaning that the laws of physics, when you look from the past into the future, are different compared to when you look from the future into the past. For example, the entropy of a closed system increases as you move from the past into the future. We suspect that the Arrow of Time is at least as real as the lack of any privileged direction in space.
Cursor of Time
There is a specific moment in time we call “now” as we perceive it constantly moving from the past into the future. It naїvely feels like “now” moves synchronously for all observers in the universe, i.e., all the observers would agree that today is Tuesday all across the entire universe. We know this is not true. We know that for causally disconnected events, there are observers who would disagree even about the order of these events. In other words, the consistent for all observers notion of “now” doesn’t exist. “Now” doesn’t show up in any formulas or models in physics either. In order to “move” from the past to the future, “now” would need its own Dimension of Time, Arrow of Time, and Cursor of Time to move in, making the definition of Time recursive.
Cursor of Time is an illusion
Moreover, we suspect that Cursor of Time is one out of the multitude of Qualia. Hence, Cursor of Time is as illusory as redness of color red, or Personal Identity.
We have no idea how to explain the phenomenon of Qualia. We have no better definition for qualia rather than point our finger at it and say: “O! This is Qualia!” And if you disagree that you see anything unusual where I point my finger at, I wouldn’t be able to prove otherwise.
Hard Problem of Cursor of Time
We know that the problem of Personal Identity is hard, so we, rather unsurprisingly, call it the Hard Problem of Personal Identity. Thus, we can conclude that we also have the Hard Problem of Cursor of Time as we believe they root in the same unexplained phenomenon.
