Recently, Eric Drexler and Richard Smalley debated the possibility of molecular nanotechnology in "Chemical & Engineering News": http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html Drexler thinks molecular manufacturing is possible (there's a lot of interesting speculation about the consequences in Engines of Creation, and the science is made more rigorous in e.g. Nanosystems); Smalley thinks it's impossible (or very limited in scope). Is anyone here able to assess the truth of all these claims? I'm confused. Or does anyone have opinions about the consequences for policy? It seems that based on Smalley's low opinion of the field, the National Nanotechnology Initiative is ignoring research into molecular manufacturing altogether. This doesn't seem wise to me, considering the potential consequences.