Edward Witten

As for the forces, electromagnetism and gravity we experience in everyday life. But the weak and strong forces are beyond our ordinary experience. So in physics, lots of the basic building blocks take 20th- or perhaps 21st-century equipment to explore.

If I take the theory as we have it now, literally, I would conclude that extra dimensions really exist. They're part of nature. We don't really know how big they are yet, but we hope to explore that in various ways.

The question is not whether Tibet should be independent but the extent of the autonomy that it is allowed. Tibet has been firmly ensconced as part of the Chinese empire since the Qing dynasty's military intervention in Tibet in the early 18th century.