The drexler-smalley debate on nanotechnology: Incommensurability at work?

In a recent debate, Eric Drexler and Richard Smalley have discussed the chemical and physical possibility of constructing molecular assemblers – devices that guide chemical reactions by placing, with atomic precision, reactive molecules. Drexler insisted on the mechanical feasibility of such assemblers, whereas Smalley resisted the idea that such devices could be chemically constructed, because we do not have the required control. Underlying the debate, there are differences regarding the appropriate goals, methods, and theories of nanotechnology, and the appropriate way of conceptualizing molecular assemblers. Not surprisingly, incommensurability emerges. In this paper, I assess the main features of the debate, the levels of the emerging incommensurability, and indicate one way in which the debate could be decided.