In 2003, C&EN published an extraordinary exchange between two of the seminal figures in nanotechnology: K. Eric Drexler, whose 1986 book “The Engines of Creation” introduced the word “nanotechnology” and the idea of “molecular assemblers,” nanoscale machines that could manipulate atoms and molecules precisely; and Richard E. Smalley, the Rice University chemistry and physics professor who won the 1996 Nobel Prize in Chemistry for the discovery of fullerenes and became a tireless champion for a National Nanotechnology Initiative (NNI) in the late 1990s (C&EN, Dec. 1, 2003, page 37). Smalley died in 2005.
The genesis of this Point/Counterpoint in C&EN was an article by Smalley that appeared in the September 2001 Scientific American titled “Of Chemistry, Love and Nanobots” in which he argued, essentially, that the molecular assemblers posited by Drexler (although Smalley never mentioned Drexler by name) were physically impossible. Smalley metaphorically outlined what he called the “fat fingers problem” and the “sticky fingers problem” to argue against the possibility of molecular assemblers.
“Both these problems are fundamental,” Smalley wrote, “and neither can be avoided. Self-replicating, mechanical nanobots are simply not possible in our world. To put every atom in its place—the vision articulated by some nanotechnologists—would require magic fingers. Such a nanobot will never become more than a futurist’s daydream.”
In early 2003, Drexler posted an open letter to Smalley challenging him to clarify his fat fingers and sticky fingers problems. C&EN’s Point/Counterpoint (which can be accessed free of charge in C&EN Archives) begins with Drexler’s open letter. In three subsequent letters, Smalley responds to the open letter, Drexler counters, and Smalley concludes the exchange.
This history is relevant because Drexler has published a new book, “Radical Abundance: How a Revolution in Nanotechnology Will Change Civilization,” that, in exhaustive and repetitive detail, updates his vision of how “atomically precise manufacturing” (APM) will transform how humans produce just about everything. Drexler’s arguments are far from convincing because, as Smalley pointed out a decade ago, they rest on a faulty premise, what amounts to magical thinking.
Drexler is a hard fellow to pin down. His own bio states that he “was awarded a Ph.D. in Molecular Nanotechnology from the Massachusetts Institute of Technology (the first degree of its kind).” The Wikipedia entry on Drexler indicates that he received a B.S. from MIT in “interdisciplinary sciences,” an M.S. in “astro/aerospace engineering,” and a Ph.D. “under the auspices of the MIT Media Lab.”
The fact is that Drexler is not a scientist and has never done laboratory research. All of his publications have been speculative, and he’s never built or even tried to build any of the machines he imagines. He is obsessed with “scaling” things and suggests that by enlarging nanoscale objects millions of times one can understand how they would work. He writes, for example: “With rigid solids and surfaces that can slide or roll (together with a few other straightforward components, like springs and brakes), almost the whole of mechanical engineering follows with surprisingly few differences other than scale. Thus, most of what we understand about machines and machine systems—familiar parts of the modern world—carries over to the design of nanomechanical systems that can do the work needed for atomically precise manufacturing. And because the scaled view is both qualitatively and quantitatively accurate, informal understanding and engineering analysis coincide.”
But that’s just not true. What makes the nanoscale interesting to scientists and engineers is just the opposite of what Drexler is claiming. Scaling, in fact, breaks down at the nanoscale. Nanoscale materials have different properties and behave differently than their bulk counterparts, making them interesting for a wide range of applications.
Drexler is up-to-date and fully conversant with most areas of current nanoscience and nanotechnology research, which makes reading “Radical Abundance” a disorienting experience. You’ll be reading a completely coherent explanation of ribosomes as examples of nanomachines or a concise summary of the capabilities of modern organic synthesis, and then suddenly you’re in the realm of teeny-tiny machines manipulating atoms and molecules with exact precision and transforming the world of manufacturing.
And make no mistake, we’re talking about teeny-tiny machines nested inside of just slightly larger machines nested inside of larger machines all the way up to a machine that can produce a car. An extended quote is necessary to capture Drexler’s vision:
“Picture yourself standing outside the final assembly chamber of a large-product APM system and looking in through a window to view the machines at work in a space the size of a one-car garage. (There’s no magnification here.)
“To the right, you see an exit door for products ready for delivery. To the left, you see what look like wall-to-wall, floor-to-ceiling shelves, with each shelf partitioned to make a row of box-shaped chambers. In the middle of the garage-sized chamber in front of you is a movable lift surrounded by a set of machines. …
“Looking back at the wall on the left, you can get a clear view into several chambers that happen to be at eye level and near the window. Each smaller chamber contains machines with swinging arms, and the overall setup inside looks like a scale model of the large chamber, complete with a rear wall with wall-to-wall, top-to-bottom rows of yet smaller chambers. It’s hard to see in detail what these small chambers-within-chambers contain, but they seem to hold a tiny yet familiar set of machines mounted in front of a rear wall with rows of yet smaller chambers.”
All the way down to invisible molecular assemblers composed of nanoscale gears and springs and mechanical arms hoisting molecules into position to react quite precisely with other molecules. Late in “Radical Abundance” Drexler explicitly states: “An APM system is a factory in a box, a compact device packed with motors, gears, conveyor belts, and specialized gadgets of various sizes. … Inside the box, small, simple machines bring molecules together to build nanoscale parts, then larger machines bring small parts together to build larger parts, and at the end, machines of ordinary size bring parts together to build final products.”
Apart from the fact that the laws of nature make such a contraption physically impossible, it’s not clear to this chemist why one would want to build it in the first place. Atomically precise manufacturing is exactly what chemists do and what the chemical industry does already on a very large scale. It’s what computer chip manufacturers do, also on a very large scale. One of the many exasperating aspects of “Radical Abundance” is that Drexler never makes clear why his vision of APM would change anything. He just seems to think that it’s clear that it will eliminate pollution, solve our energy problem, halt climate change, and make human labor virtually unnecessary, with radically disruptive results.
There are many other elements of “Radical Abundance,” some interesting, some less so. Drexler provides a long and fairly insightful discussion of the differences between science and engineering, for example. His discussion of how his conception of nanotechnology was hijacked by the likes of Smalley and other backers of NNI borders on the paranoid. He just doesn’t understand that his conception of nanotechnology is a fantasy.
That makes the many, many pages of “Radical Abundance” devoted to how APM will change civilization superfluous. As Smalley wrote to Drexler in the concluding letter in the C&EN Point/Counterpoint: “You don’t get it. You are still in a pretend world where atoms go where you want because your computer program directs them to go there.” Nanoscience and nanotechnology—the real disciplines, not Drexler’s imaginary one—have huge potential to benefit humans and Earth. “Radical Abundance” is not the place to learn about them.
Rudy Baum is C&EN editor-at-large.