What is the difference between Drexlerian Nano and Non-Drexlerian?
Before Drexler, there was a talk by the physicist Richard Feynman (“There’s Plenty of Room at the Bottom”) where he envisioned the possibility of building things with atomic precision. He didn’t flesh out the implications of self-replicating assemblers, as has since been done by Drexler and others. Feynman did imagine a path for getting to a working nanotechnology. He imagined building a set of machine tools (lathes, mills, drills, etc.) which could be used to build a second set of machine tools, one-tenth the size of the first set. You’d also need to build controls that would allow you to operate the second set of machine tools, either manually or with computer automation. Then you’d use the second set to build a third set, one-hundredth the size of the first set, along with any necessary controls. You continue this until you get tools that can directly push atoms around, and make and break chemical bonds. (However,) some things scale linearly, some quadratically, and some as the cube
