Well I've been working on three issues. One of them we discussed already, and that is the work with Jim Hartle on trying to understand a reasonable basis for quantum mechanics. A second one, which is not unrelated, is to understand something about issues of simplicity and complexity. I call that whole field 'plectics' from a Greek word for braided, plectos, related to the Latin root, plexus, which originally also meant braided and from which we get complexes—complex; braided together. But it's related distantly also to the Latin verb plecare, they both come from the same Indo-European root, plec. Plecare means to fold, and simplex originally was once folded, and that gives simple or simplicity. So simplicity and complexity are related, once folded and braided together, and it's interesting that the word we're using refers to braiding or folding because entanglement is essential of course to produce anything that has any sort of diversity, complexity, individuality. If we were all just made of independent, of…of quarks and electrons in independent states we wouldn't have much… many properties of interest. So I think plectics is an excellent word, and it's non-committal with respect to whether you're discussing the simple laws or their complex consequences.

Anyway, quantum mechanics is one subject. The second subject is understanding something about simplicity and complexity, logical depth, chaos, trade-offs, trade-offs between logical depth and effective complexity, and so on and so forth. On all of this I've been co-operating with Seth Lloyd who is now an Associate Professor of Mechanical Engineering at MIT, although he was trained as a physicist, and he works on a lot on quantum computers, so he says he's a professor of quantum mechanical engineering at MIT, and of course Jim Hartle has played some role in that too. And the third subject, that I've been working on these last years, and especially recently, is the typology of scaling phenomena, and you and Juan Pérez-Mercader and Jim Brown and I are trying to get NASA support for our work on the typology of scaling phenomena. Is it really true that all scaling phenomena in all fields have something to do with one another? Or are there different kinds of scaling and may be some slight mathematical differences among the different kinds of scaling, and so on? It's a very exciting subject, I think. I've been fascinated with Zipf's law for cities and things like that for fifty years now, since I first heard about it from Viki Weisskopf, my thesis adviser, and trying to understand what sorts of relations there are among different scaling phenomena and different explanations for scaling phenomena would be very exciting.