First was theory, I told you, and then there were experiments, we said we can't simply make theory. We have to find out that we do the right theory, or the relevant type of theory, and that we did by those experiments. And then we found, yes, we can even do theories for... experiments for things where you cannot do the theory. This evolution experiment, you cannot calculate it, the evolution tells you the system will find the optimal solution, and it did so, but the way how it did it nobody would have guessed before. So this established the technological principle, and now comes the third phase that we built machines for the purpose of using them for finding new substances and this is an entirely new phase in our work.

Before I get to this phase I should say perhaps a little more about theory... about Peter Schuster. I cannot introduce you into this theory of highly non-linear networks, but I can say what are the problems and what are the type of solutions we look for, and let's just start with that.

[Q] That's a good idea. But I would like to say the following. I have learned, being with you for more than thirty years, that you are a person, a scientist, who says, 'No theory without experiments, no experiments without theory'. So this just... that's your slogan for your science but this is...

That's the way physics works.

[Q] Yes, but there are physicists who only concentrate on theory, and you combine it in a... I would say a very efficient way, otherwise the evolution...

There was one great physicist who really placed the theory above everything, that was Albert Einstein. When Einstein founded general relativity there was no experimental... no proof... but there was no experimental evidence on which he could base his theory. It was made a theory out of his head, and it turned out to be a right theory. The special relativity, you could say there was the Michelson-Morley experiment which said that light velocity is independent of the system in which... so you cannot add velocity, the light velocity is an absolute way an upper limit of velocity and also that the light velocity was a limiting velocity came out of Maxwell's electromagnetic theory. So you could say, all right, for special relativity there were some hints - but still, I mean it... surprising results. Einstein made a theory of relativity to become independent of time and space and out came a relation like that mass is equivalent to energy and vice versa. And then in gravitation theory mass determines... bends the space, and causes light beams to be deflected by mass.

There was no experimental proof by then and it took quite some time and it turned out to be right. All other theories I think have been based on experimental facts. Think quantum mechanics, we had quantum theory, it was recognised by Planck and Einstein with his photoelectric law, that energy is quantized. But then people tried to understand the spectra and it didn't work. They knew there is a new theory which has to come and which has to be described and Heisenberg and Schrödinger independently found this new type of theory and it turned out to be equivalent to one another.