We've come a pretty long way, haven't we?

Our journey started in the 1910s, that's over 100 years ago, with the first hints of some techniques, some ideas that wouldn't

lead to string theory directly, but would be folded into string theory, like Calusa and Klein

in these extra dimensions and attempts at unification. And we found in the 1940s the story of Heisenberg in the scattering

matrix theory that went nowhere, but how it was tried again in the 1960s to explain this

newfangled strong force that the kids are all talking about. And it kind of failed pretty hard on that count too for several reasons.

But hidden in the math of the S matrix theory when applied to the strong force was strings.

Then the concept of strings required small, extra curled up dimensions, or whatever, I guess.

That's just the way the universe is.

And in the 70s, we invented supersymmetry to be able to incorporate fermions, which are

the building blocks of matter, into this theory of stringy goodness.

And by the mid-1970s, everything was pretty groovy, man.

String theory could potentially explain the origin of matter and the forces of nature,

you know, maybe, hard to tell, since still using perturbation methods.

We didn't have a full string theory that we could point to.

We just had a bunch of approximations that we hoped were somewhat close to the actual theory.

And we couldn't really make predictions with this theory because it was too complicated,

like even with the approximations. And there's the whole business about the extra dimensions and how

they're curled up and how they affect the physics of the strings, and we can really understand

that connection.

So, you know, we had some cool ideas in the 70s, didn't everybody.

And I presented this as a somewhat linear story, but of course it wasn't. It was full of the usual twists and turns and blind alleys of typical of any research program, so it shouldn't be a surprise that 1974 came as a big surprise.

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