Time has been called one of the universe's biggest mysteries and there's little wonder why. What is time? In what sense does time exist? Is time, like Immanuel Kant thought, simply the way our minds structure experience or does time actually exist objectively, independently of human beings and other perceivers?
Physicist Brian Greene discusses time in this video and argues that our experience of past, present, and future is a kind of illusion. There is, he argues, no definite, objective past. The same is true for the present and the future.
This may seem very strange to you if you're hearing this for the first time (no pun intended) so take a look: