Editing Molecular nanotechnology (section)

===Assemblers versus nanofactories===
A section heading in Drexler's ''[[Engines of Creation]]'' reads<ref>{{cite web|url=http://www.e-drexler.com/d/06/00/EOC/EOC_Cover.html |title=Engines of Creation - K. Eric Drexler : Cover |publisher=E-drexler.com |access-date=2010-09-05}}</ref> "Universal Assemblers", and the following text speaks of multiple types of [[Assembler (nanotechnology)|assemblers]] which, collectively, could hypothetically "build almost anything that the laws of nature allow to exist." Drexler's colleague [[Ralph Merkle]] has noted that, contrary to widespread legend,<ref>{{cite web|url=http://www.foresight.org/impact/impossible.html#Fear |title=How good scientists reach bad conclusions |publisher=Foresight.org |access-date=2010-09-05}}</ref> Drexler never claimed that assembler systems could build absolutely any molecular structure. The endnotes in Drexler's book explain the qualification "almost": "For example, a delicate structure might be designed that, like a stone arch, would self-destruct unless all its pieces were already in place. If there were no room in the design for the placement and removal of a scaffolding, then the structure might be impossible to build. Few structures of practical interest seem likely to exhibit such a problem, however."

In 1992, Drexler published ''Nanosystems: Molecular Machinery, Manufacturing, and Computation'',<ref>{{cite web|url=http://www.e-drexler.com/d/06/00/Nanosystems/toc.html |title=Nanosystems TOC |publisher=E-drexler.com |date=2002-11-01 |access-date=2010-09-05}}</ref> a detailed proposal for synthesizing stiff covalent structures using a table-top factory. [[Diamondoid]] structures and other stiff covalent structures, if achieved, would have a wide range of possible applications, going far beyond current [[Microelectromechanical systems|MEMS]] technology. An outline of a path was put forward in 1992 for building a table-top factory in the absence of an assembler. Other researchers have begun advancing tentative, alternative proposed paths <ref name="autogenerated3" /> for this in the years since Nanosystems was published.