Time

Is time a 'real thing' or is it only a useful idea created by human minds?

I think in physics, it's treated as a physical thing (spacetime), yet some philosophers have said that time is not real.

Is there a simple answer to this question, and if so, what is it?

Philosophically, time is not very well defined. We all accept that there is a dimension called time and that time moves in one direction. Time is the dimension that allows differentiation between one event and the next. Without it, there could be no events. It isn't an arbitrary thing, like time zones or reference frames, due to this necessity.

However, we cannot be sure about how time "behaves." We naively believe that time moves forward at the same pace for everyone, but this may not be the case. Time, like some things, is noumenal in nature, meaning that our perception of it occurs by virtue of it. We cannot perceive it from the outside. If time passed half as fast for you as for me, there would be NO way of telling, because it dictates how we perceive things.