I've encountered a lot of people who sound like critics but very few who have substantive criticisms. There is a lot of skepticism, but it seems to be more a matter of inertia than it is of people having some real reason for thinking something else.

Scientists study physical things, then describe them; engineers describe physical things, then build them.

Protein engineering is a technology of molecular machines - of molecular machines that are part of replicators - and so it comes from an area that already raises some of the issues that nanotechnology will raise.

Likewise nanotechnology will, once it gets under way, depend on the tools we have then and our ability to use them, and not on the steps that got us there.

On the molecular scale, you find it's reasonable to have a machine that does a million steps per second, a mechanical system that works at computer speeds.

An international race in the relevant technologies is getting under way at this point, not necessarily with an understanding of where that race leads in the long run, but strongly motivated by the short-term payoffs.

I had been impressed by the fact that biological systems were based on molecular machines and that we were learning to design and build these sorts of things.