For some odd reason, there seems to be a lot of such discussion on the internet, be it in some crackpot website, or on various online forums. And the strange thing about it is that, more often than not, such a discussion is based on, of all things, philosophical arguments and not on physical grounds at all! Most argued that time is a construct of the human mind (as if the rest of what we observe isn't), and that it isn't as "fundamental" as space, etc. In almost all cases, these arguments seem to have overlooked (or maybe they are ignorant of them) a large body of knowledge in physics, and inevitably, never try to address the dynamics of the universe without "time".
Now this is not to say that there isn't a legitimate question on this. One of the things that we try to decipher about the universe is the question on how many fundamental constants are there. Constants such as the fine structure constant can be dimensionless, and thus, such a constant is not dependent on our measuring scale. What ever is the most minimum set of constants that we need to completely describe the universe that we are aware of, then the dimension of such constants will require the minimum corresponding scale. For example, if the speed of light is a fundamental constant, then the concept of both space AND time is the most minimum set of dimensions that we require to allow for "c", since it is a measurement of how much space light has moved in a particular period of time. You cannot simply have just space or just time to be able to define "c" as a quantity.
So what would be the impetus for someone to claim that time is an illusion or isn't fundamental? The most common and most feeble argument that I have seen is the application of Special Relativity's consequence that time "can change" with respect to an observer in different inertial frames. This includes the time dilation effect, and the inability to agree on what is "simultaneous". The other most common argument is the notion that time is nothing more than a measure of displacement, and so, space is more fundamental.
Here, I am not going to try and argue that time isn't fundamental, or time isn't an illusion. We still haven't figured out yet what is meant by an "illusion", since such a word seemed perfectly obvious to the people involved in the philosophical discussion (no one asked the definition of the word, at least not that I have seen). It certainly isn't a physics concept. What I will try to do is point out holes and inconsistencies in such an idea, and that most of these people are actually missing huge chunks of physics that they are ignoring in putting forth their argument. So essentially, this could easily be another "Imagination Without Knowledge is Ignorance Waiting to Happen" entry.
1. Time changes in Special Relativity.
Sure it does! But so does space! Time dilation AND length contraction are two of the consequences of the postulates of Special Relativity. So why pick on time alone?
2. Time is simply a measure of displacement.
How would you actually MEASURE spatial distances? How does one determine Point A is at some distance away from Point B? Use a ruler? How did we arrive at that ruler? What if the distance is huge? Inevitably, this will lead to using light (as Einstein did) in DEFINING what we mean by space and time. That the idea of space is based on the distance that light traveled in a particular period of time, and the idea of time also follows in the same manner. So here, space and time are certainly interlocked, and one isn't more fundamental than the other.
3. In Special and General Relativity, time and space occupy the same degree of importance. They share the same platform, and they are interconnected as the Minkowsky spacetime manifold. So someone who claims time is an illusion or isn't fundamental seems to have ignored or dismissed SR and GR, and did so without any explanation.
4. In elementary particle physics, the concept of space and time are contained in the P and T symmetry (for parity and time). The generally accepted idea out of the Standard Model is that CPT (C=charge conjugation) symmetry is conserved, while we have seen CP and T being violated separately. Regardless of whether we eventually see CPT violation, the fact that the time symmetry operation shares the same degree of importance as parity and charge as one of the fundamental symmetries of the universe seems to have been lost in this argument. Why is such an issue never brought up and explained away?
5. In many well-known phenomena, the appearance of violation of time-reversal symmetry indicates the existence of a profound transition. The transition from the normal state into a superconducting state in unconventional superconductors is one such example. The broken time-reversal symmetry is an important clue on the transition point of such a phenomenon. If this is an "illusion", someone has a lot of explaining to do.
6. Radioactive decay doesn't care if we have a "mind" or not. It will take the same amount of time no matter if we designate time as fundamental or an illusion. Considering that at a single nuclear level, this is a random process and yet as a conglomerate of nuclei, they all somehow "know" the decay rate that they have to "obey", I'd say that these nuclei know about "time" and respect it.
These arguments are just the beginning. For some reason, most of those who are involved in such arguments never seem to address any of these issues, but rather seem to think that one can arrive at a conclusion simply based on "logic" and word games. Somehow, evidence and observation of our physical world aren't an important factor in deciding such a thing. Or maybe they know that they can't address these points and decide to ignore them.