In what I consider one of the most visionary talks in a long while, Columbia professor Brian Greene gave a pithy 20-minute presentation about the possibility of multiverse, or multiple universes, and its implications. I’ve never even taken physics, so I’m not going to embarrass myself here trying to explain string theory–you can get a for-dummies version from Brian Greene in the TED talk video or here.

The talk is great not because Greene presented what the mysteries of physical science mean for the possibility of multiverse; as one friend of mine said after I urged him to watch the talk: “I don’t need to watch this video, I’ve learned it three years ago.” But I do believe the fact that the idea of a multiverse is no longer a pure sci-fi fantasy but a very real possibility–in other words, its transition from imagination to speculation–is absolutely groundbreaking in that our ways of thinking about science, philosophy, and just about everything might have to be changed completely.

What is far more important is Greene’s concluding remarks about the distant future, when the galaxies had rushed so far away from us that we will not be able to see them even with the absolute best technology “because the light will never traverse the ever-widening gap between us.” We will see nothing but “an endless stretch of static, inky black stillness.” The astronomers will have the ancient records at hand, but they might conclude “that the universe is static and unchanging and populated by the single oasis of matter they habit” and the ancient records “a picture of cosmos we definitely know to be wrong” because the records contradict what they see and observe with the technology that will be infinitely better than ours. This picture is reminiscent of our attitudes toward certain mysteries of the past, and I think its implications go far beyond Greene’s conclusion that we live in an extremely privileged age when the physical nature had not left us all alone in the space.

I think what Greene’s vision signifies is the limitation of mankind and the possibilities of reality. Human beings have only existed for a very, very tiny fraction of space time (and we, those who are living now, are nothing compared to the much grander history of everything); we are extremely limited in what we could, can, and will be able to see. But just because we can’t see or prove something in the present time doesn’t mean that it has never existed or will never exist. This “something” could be  anything ranging from multiverse to other galaxies to ancient aliens to religious beliefs. What appears real to us might not be real at all because we are so limited in our capabilities. This is not to say that we should just give credit to anyone with a crazy story. It just means that we should always question the certainty of our beliefs. Perhaps Descartes was has found the only truth: that I exist is the only thing we are certain. I just feel so humbled by the unknowns, and I feel so alive and energized knowing that the world around me has endless possibilities.