SG: Aw shucks! I could say equally nice things about each of them, too.
I think maybe their kind comments have something to do with the fact that after 20 years of hard work I became an overnight success. If you think Creatures emerged fully formed out of a vacuum, you'd probably conclude that I'm a genius, but really I'd spent all my adult life thinking about these things quietly to myself and doing experiments that no-one else saw. In a way this is the downside of working alone -- nobody even knows you exist until you produce something. That's more or less the position I'm in now, because it's ten years since Creatures was published, and the work that I started with Lucy the Robot is going to take a while yet to come to fruition (forever, unless I earn some money!). But the good side of it is that nobody is looking over my shoulder all the time, tracking every little bit of progress.
Even so, one of the most important things that these guys happen to know is just how hard the problem is, and I'm glad they think I'm on the right track. I suppose it's fair to say that Richard Dawkins is a (surprisingly rare) believer that there are fundamental principles in biology, which is why he was present at the first ever conference on artificial life, and in my work I try to discover and exploit some of those principles, looking for the simplest, most elegant computational structures that can create lifelike richness. Meanwhile, Dan Dennett and Rod Brooks have always pointed out the importance of building complete organisms, in which the whole can become more than the sum of its parts, and that's what I try to do as well.
But I think one of the most important aspects of my work is the way I think about computation. Since the development of the computer we've all been conditioned to think of computation as a digital, serial, stepwise process in which varying sets of instructions are used to control data. So many of our metaphors for understanding the world are now set within this paradigm. But living things, brains, social systems, and for that matter most things in the universe compute almost instantaneously, in a massively parallel, analogue way. What's more, it's the 'data' that drive the 'code', in the sense that the laws of physics (the "instructions") are fixed and universal, and all the richness we see around us is due to the changing relationships between objects. It seems to me that my job as a creator of simulations should involve taking the serial, top-down, digital computer and turning it as quickly as possible into a simulation of a parallel, analogue, bottom-up, data-driven system. From that point on I should simply arrange virtual objects in space and alter their parameters -- the way the real world works. Basically I start out as a programmer and then switch as early as possible to being a biologist. I think this is important, but most people in AI, A-life and computer science find the digital paradigm a hard habit to shake.