Michael Abrash, the chief scientist for Facebook's Oculus, took the stage during day two of the F8 Developer Conference in San Francisco to blow everyone's mind with some trippy optical illusions. During the keynote, Abrash highlighted some interesting illusions to explain how we can trick our eyes into thinking what we're seeing is reality. And according to Abrash, these perceptions, and the assumptions our brain makes about them, are what make virtual reality work.

“This is not remarkable, for, as we know, reality is not a function of the event as event, but of the relationship of that event to past, and future, events. We seem here to have a paradox: that the reality of an event, which is not real in itself, arises from the other events which, likewise, in themselves are not real. But this only affirms what we must affirm: that direction is all. And only as we realize this do we live, for our own identity is dependent upon this principal.“

-Robert Penn

To understand more about how our mind can see things which may not even exist, take a gander at this interesting clip below.