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Drexler writes Smalley open letter on assemblers

Foresight Chairman K. Eric Drexler has sent Nobel laureate Richard Smalley an open letter to rebut Smalley's statements that molecular assemblers are not possible. The letter was also sent directly to several dozen leading researchers, decision makers, and journalists in the field. Reportedly Prof. Smalley has promised a response.

Drexler wrote to Smalley:

Prof. Smalley:

I have written this open letter to correct your public misrepresentation of my work.

As you know, I introduced the term "nanotechnology" in the mid-1980s to describe advanced capabilities based on molecular assemblers: proposed devices able to guide chemical reactions by positioning reactive molecules with atomic precision. Since "nanotechnology" is now used label diverse current activities, I have attempted to minimize confusion by relabelling the longer term goal "molecular manufacturing". The consequences of molecular manufacturing are widely understood to be enormous, posing opportunities and dangers of first-rank importance to the long-term security of the United States and the world. Theoretical studies of its implementation and capabilities are therefore of more than academic interest, and are akin to pre-Sputnik studies of spaceflight, or to pre-Manhattan-Project calculations regarding nuclear chain reactions.

You have attempted to dismiss my work in this field by misrepresenting it. From what I hear of a press conference at the recent NNI conference, you continue to do so. In particular, you have described molecular assemblers as having multiple "fingers" that manipulate individual atoms and suffer from so-called "fat finger" and "sticky finger" problems, and you have dismissed their feasibility on this basis [1]. I find this puzzling because, like enzymes and ribosomes, proposed assemblers neither have nor need these "Smalley fingers" [2]. The task of positioning reactive molecules simply doesn't require them.

I have a twenty year history of technical publications in this area [3 - 12] and consistently describe systems quite unlike the straw man you attack. My proposal is, and always has been, to guide the chemical synthesis of complex structures by mechanically positioning reactive molecules, not by manipulating individual atoms. This proposal has been defended successfully again and again, in journal articles, in my MIT doctoral thesis, and before scientific audiences around the world. It rests on well-established physical principles.

The impossibility of "Smalley fingers" has raised no concern in the research community because these fingers solve no problems and thus appear in no proposals. Your reliance on this straw-man attack might lead a thoughtful observer to suspect that no one has identified a valid criticism of my work. For this I should, perhaps, thank you.

You apparently fear that my warnings of long-term dangers [13] will hinder funding of current research, stating that "We should not let this fuzzy-minded nightmare dream scare us away from nanotechnology....NNI should go forward" [14]. However, I have from the beginning argued that the potential for abuse of advanced nanotechnologies makes vigorous research by the U.S and its allies imperative [13]. Many have found these arguments persuasive. In an open discussion, I believe they will prevail. In contrast, your attempt to calm the public through false claims of impossibility will inevitably fail, placing your colleagues at risk of a destructive backlash.

Your misdirected arguments have needlessly confused public discussion of genuine long-term security concerns. If you value the accuracy of information used in decisions of importance to national and global security, I urge you to seek some way to help set the record straight. Endorsing calls for an independent scientific review of molecular manufacturing concepts [15] would be constructive.

A scientist whose research I respect has observed that "when a scientist says something is possible, they're probably underestimating how long it will take. But if they say it's impossible, they're probably wrong." The scientist quoted is, of course, yourself [16].

K. Eric Drexler Chairman, Foresight Institute


1. Smalley, R. E. (2001) Of chemistry, love and nanobots - How soon will we see the nanometer-scale robots envisaged by K. Eric Drexler and other molecular nanotechologists? The simple answer is never. Scientific American, September, 68-69.

2. Drexler, K. E., D. Forrest, R. A. Freitas Jr., J. S. Hall, N. Jacobstein, T. McKendree, R. Merkle, C. Peterson (2001) A Debate About Assemblers.

3. Drexler, K. E. (1981) Molecular engineering: An approach to the development of general capabilities for molecular manipulation. Proc. Natnl. Acad. Sci. U.S.A.. 78:5275-5278.

4. Drexler, K. E. (1987) Nanomachinery: Atomically precise gears and bearings. IEEE Micro Robots and Teleoperators Workshop. Hyannis, Massachusetts: IEEE.

5. Drexler, K. E., and J. S. Foster. (1990) Synthetic tips. Nature. 343:600.

6. Drexler, K. E. (1991) Molecular tip arrays for molecular imaging and nanofabrication. Journal of Vacuum Science and Technology-B. 9:1394-1397.

7. Drexler K. E., (1991) Molecular Machinery and Manufacturing with Applications to Computation. MIT doctoral thesis.

8. Drexler, K. E. (1992) Nanosystems: Molecular Machinery, Manufacturing, and Computation. New York: John Wiley & Sons.

9. Drexler, K. E. (1992) Molecular Directions in Nanotechnology. Nanotechnology (2:113).

10. Drexler, K. E. (1994) Molecular machines: physical principles and implementation strategies. Annual Review of Biophysics and Biomolecular Structure (23:337-405).

11. Drexler, K. E. (1995) Molecular manufacturing: perspectives on the ultimate limits of fabrication. Phil. Trans. R. Soc. London A (353:323-331).

12. Drexler, K. E. (1999) Building molecular machine systems. Trends in Biotechnology, 17: 5-7.

13. Drexler, K. E. (1986) Engines of Creation: The Coming Era of Nanotechnology. New York: Anchor Press/Doubleday.

14. Smalley, R. E. (2000) quoted in: W. Schulz, Crafting A National Nanotechnology Effort. Chemical & Engineering News, October 16.

15. Peterson, C. L. Testimony before the Committee on Science, U.S. House of Representatives, 9 April 2003.

16. Smalley, R. E. (2000) quoted in N. Thompson, Downsizing: Nanotechnology---Why you should sweat the small stuff . The Washington Monthly Online, October.



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