So what is time and how do you measure it?

If you postulate the existence of something (or somebody) static, outside of you, "wrapped in plastic" and immutable, then time could be conceived somehow around this concept. This static, "wrapped in plastic" phenomenon - being it the creation of the world, if you want - can be equaled with the "beginning". And from there you can measure it.

Unfortunately, there is no such thing. Nothing exists "outside", wrapped in plastic, by itself. Everything is connected to everything and everything is continuously changing.

Our cognition is based on three things: us, (the perceiver), the other (the perceived) and the action with which we're taking into cognition the other. Everything that exists is created like this. It's the same thing that quantum physics postulates: "an event is dependent on its observer".

So time is a subjective dimension, defined as the totality of the memories we generate as we "advance" in a mental continuum. Hence, it cannot be measured objectively.

The quotation marks around "advance" are signaling the fact that we're not really "advancing", but we're rather "propelled" by our own actions and desires. Once we stop having desires and actions, the "advancing" stops, samsara - the world of illusion in which we're living right now - collapses and we're enlightened.

Still working on that :)