Andrew Strominger

Now, at the same time, it was believed then that string theory was an interesting sort of toy model for putting quantum mechanics and general relativity together on paper, but that it couldn't describe some of the very idiosyncratic phenomena that pertain to our own universe, in particular, the form of so-called parity violations.

Yeah, yeah.

And you look in the mirror across the bar.

Yes.

The universe that you see in the mirror is not identical.

You would be able to tell if you show the lady in the bar a photograph that shows both the mirror and you.

If she's smart enough, she'll be able to tell which one is the real world and which one is you.

Now, she would have to do some very precise measurements.

And if the photograph was too grainy, it might not be possible.

No, it's a very interesting feature of the real world that it isn't parity of invariant.

In string theory, it was thought could not tolerate that.

And then it was learned in the mid-'80s that not only could it tolerate that, but if you did things in the right way, you could construct a world involving strings that reconciled quantum mechanics and general relativity, which looked more or less like the world that we live in.

And now, that isn't to say that string theory predicted our world.

It just meant that it was consistent, that the hypothesis that string theory describes our world can't be ruled out from the get-go.

And it is also the only hypothesis

for a complete theory that would describe our world.

Still, nobody will believe it

until there's some kind of direct experiment.

And I don't even believe it myself.

Well, then when he was wrong about that.