One of the crowning achievements of Einstein’s Relativity is to conceptualize the movement of the universe through time as a 4-dimensional spacetime. With this paradigm, one can study the universe without reference to change through time, but rather in terms of pure geometry of spacetime. In effect, time becomes indistinguishable from space, and thus all the beautiful mathematical techniques to investigate properties of space (i.e. differential topology) can be extended to include time.
However, Lee Smolin beautifully argues that any mathematical representation of the universe we have doesn’t capture a fundamental property of our experience—namely, that time is NOT like space. In the universe, it is always some moment in time. Therefore, he argues, any better theory of nature must account for the existence of time—real, actual time, not just a disguised dimension of space.
As of now, I cannot seem to escape the conclusion that time may be illusory, but I look forward to reading more about Smolin’s counterargument. It most likely has to do with Entropy, but he also needs to figure in quantum gravity. We’ll see.