Regardless of any deviations, it was clear I was supposed to end up in math and physics. – Edward Witten

One very important aspect of string theory is definitely testable. That was the prediction of supersymmetry, which emerged from string theory in the early ’70s. – Edward Witten

Quantum mechanics brought an unexpected fuzziness into physics because of quantum uncertainty, the Heisenberg uncertainty principle. String theory does so again because a point particle is replaced by a string, which is more spread out. – Edward Witten

If you are a researcher, you are trying to figure out what the question is as well as what the answer is. – Edward Witten

I have a tendency, more than most other physicists, to try to figure out everything all at once, before I publish. And even to try to figure out everything in my head, without pencil and paper. – Edward Witten

Even before string theory, especially as physics developed in the 20th century, it turned out that the equations that really work in describing nature with the most generality and the greatest simplicity are very elegant and subtle. – Edward Witten

But the beauty of Einstein’s equations, for example, is just as real to anyone who’s experienced it as the beauty of music. We’ve learned in the 20th century that the equations that work have inner harmony. – Edward Witten

On the other hand, we don’t understand the theory too completely, and because of this fuzziness of spacetime, the very concept of spacetime and spacetime dimensions isn’t precisely defined. – Edward Witten

I just think too many nice things have happened in string theory for it to be all wrong. Humans do not understand it very well, but I just don’t believe there is a big cosmic conspiracy that created this incredible thing that has nothing to do with the real world. – Edward Witten

One of the basic things about a string is that it can vibrate in many different shapes or forms, which gives music its beauty. – Edward Witten

You have that one basic string, but it can vibrate in many ways. But we’re trying to get a lot of particles because experimental physicists have discovered a lot of particles. – Edward Witten

I wouldn’t have thought that a wrong theory should lead us to understand better the ordinary quantum field theories or to have new insights about the quantum states of black holes. – Edward Witten

Quantum mechanics brought an unexpected fuzziness into physics because of quantum uncertainty, the Heisenberg uncertainty principle. – Edward Witten

String theory is an attempt at a deeper description of nature by thinking of an elementary particle not as a little point but as a little loop of vibrating string. – Edward Witten

As far as extra dimensions are concerned, very tiny extra dimensions wouldn’t be perceived in everyday life, just as atoms aren’t: we see many atoms together but we don’t see atoms individually. – Edward Witten

Technically you need the extra dimensions. At first people didn’t like them too much, but they’ve got a big benefit, which is that the ability of string theory to describe all the elementary particles and their forces along with gravity depends on using the extra dimensions. – Edward Witten

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. – Edward Witten

As of now, string theorists have no explanation of why there are three large dimensions as well as time, and the other dimensions are microscopic. Proposals about that have been all over the map. – Edward Witten

So when you ask me how string theory might be tested, I can tell you what’s likely to happen at accelerators or some parts of the theory that are likely to be tested. – Edward Witten

Spreading out the particle into a string is a step in the direction of making everything we’re familiar with fuzzy. You enter a completely new world where things aren’t at all what you’re used to. – Edward Witten

Having those extra dimensions and therefore many ways the string can vibrate in many different directions turns out to be the key to being able to describe all the particles that we see. – 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. – Edward Witten

There was a long history of speculation that in quantum gravity, unlike Einstein’s classical theory, it might be possible for the topology of spacetime to change. – Edward Witten