Source: XKCD (Randall Munroe) |
"Will time end? Time is an abstract concept created by humans. It doesn't exist and therefore never started, so it cannot end." (It's been modified slightly from its original form to protect the guilty.)
Let's start with the first postulate there: that time isn't real, that it is a human construct. Physics is essentially based on functions that take the time coordinate as an input (and some other things) and produce a position or some attribute as an output. If time isn't real, physics breaks down and there is no universe. No universe? No humans to create the system. Everything about science is based on time flowing in one direction (at least in the unrolled dimension) and the absence of cycles in time. Animals and tiny organisms, extant long before humans came to be on the earth, had to do things at certain times to stay alive. It is quite safe to say that animals such as bears change their behavior based on the time (e.g. hibernating).
Now, let's take on the proposition that time never started. Big-bang cosmology, the accepted theory in its field, depends quite heavily on there being a zero point in time (the bang). We can use super-telescopes to look far out and far back to see how matter became more advanced as time moved away from that one creation moment. The WMAP image, possibly the most important image in science, by existing proves that the Big Bang happened and that time has a beginning.
Finally, the declaration that time cannot end. The "reasoning" behind it is empty, but it's not necessarily wrong. Space is expanding (out from one beginning point), and time seems to be continuing. For time to end, spacetime would have to stop expanding or be destroyed, which may or may not be possible. We shall see, or rather the universe will see - we will most likely be long gone.