A digression nanovisions and their risk assessment

From the very beginning of nanotechnology, far-reaching visions of the future have been intrinsically associated with its development and history. One must assume that these futuristic visions - and not least the numerous and ubiquitous science fiction images of "nano-engines," consisting of only a few atomic layers, and "nanorobots," moving about in the bloodstream and fighting cancer cells, bacteria, and viruses - were instrumental in the very establishment of the idea of a "nanotechnology." It was precisely these visions that finally led to the breakthrough of the umbrella concept "nanotechnology" as a paradigm. They were able to arouse the emotions needed to carry the concept into politics, news, and public debate and to mobilize enormous amounts of funding. And of course authors such as Drexler played an important role in this.43

43 Regarding this, Summer (n.d.) writes: "The rapid development of nanotechnology is to a large extent originally due to the visions of future technological possibilities and their implications for society by a few scientists, among them especially K. Eric Drexler (see Drexler et al. 1986; Drexler 1991; Drexler 1992). Following the example of Drexler such a multitude of mainly American scientists and science journalists have created futuristic scenarios about nanotech-

Where futuristic visions such as these are to be found, reactionary horror scenarios are not far behind. An increasingly critical debate on the dangers of proliferating nano-devices began, one in which old fears were mobilized, from the magic broom run amok to robots capable of overpowering mankind (see Drexler 1986, Joy 2000). The issues of "grey goo" and mechanical self-reproduction regularly reoccur as horror scenarios intended to evoke the dangers of nanotechnology.

The starting point for such scenarios was also provided by Drexler, who developed the idea of "assemblers," machines that would be capable of producing any kind of object by extracting atoms from the environment and assembling them into a new object, atom by atom.44 These assemblers could be programmed and equipped with their own power supply. Since they would be able to produce anything they could accordingly reproduce themselves, which, in the case of malfunction could lead to an alteration of the entire biosphere (grey goo). This vision led to the demand for specific safety measures in future nanotechnological development.

Currently there is a strong trend to try to end these debates by questioning the technological feasibility of such "assemblers," mainly by means of arguments based on physics and science.45 However, (current) technological infeasibility is not an especially strong argument in the light of the technological developments of the past 150 years. At the same time major debates are being conducted and important reports published on the "convergence of information technology, nanotechnology, biotechnology, genetic engineering, and cognitive science to improve the progress of mankind" (Rocco & Bainbridge 2002). The following two illustrations are from this report on "converging technologies" and illustrate the associated visions of convergence and technological architecture of the 21st century.

nology that from this a downright new literature genre has developed, which is apparently also used by research politics in order to give a popular illustration of nanotechnology." p. 9 foll.

44 Drexler follows the line of Feynman's famous talk in 1959 "Plenty of Room at the Bottom," which today is viewed by many as nanotechnology's founding myth. Feynman 1959. http://www.its.caltech.edu/~feynman/plenty.html

45 Often problems of power supply, thermodynamics and (self-)control are treated; see, e.g., the debate between Drexler and Smalley in Chemical and Engineering News December 2003

http://pubs.acs.org/cen/coverstory/8148/8148counterpoint.html.

Computers Bktdi

Bits Genes

21st Century Aichitcctuie Neurons Atoms

Networks Nanotech

Fig. 12. Visions of convergence and a technological architecture of the 21st century46

Here at least one thing should be clear: Debate about such long-term visions of fascinating possibilities and the associated horror scenarios will continue and will scarcely be ended by decree. The social debate on nanotechnology has in large part thrived on these.

However, this does not mean that such populist visions and speculations must decide scientific technology assessment - on the contrary. We should concentrate not on speculation but on that knowledge already available to us today. This means that with regard to "converging technologies" as described above, a risk assessment based on a "characterization of the technology" must be further and resolutely pursued. On that basis some impor tant differentiations can already be made, which can also be found in the recently published report of the Royal Commission, particularly the distinction - which we have already made several times - between passive and active nanostructures, and furthermore the distinction between a "mechanical" and a "biological" path of development for nano-devices. With respect to the assessment of the risk of uncontrolled behavior or the transition from self-organization to self-replication, there are large differences between these two paths. The probability that "mechanically structured" nanorobots (nanobots or self-assemblers) would (inadvertently) self-replicate, probably is quite minimal. This is not equally true for nano-structured units based on "biological" molecules - DNA in particular, which is currently the subject of many nano-biotechnological experiments and projects - or on organelles or even cells. To a certain extent, even the simplest SAMs, the self-assembled monolayers based on "polar" molecules, are model systems after the example of "biological membranes." So the biological path to nano-devices should be, by far, the more promising (and more worrisome). David Pescovitz of UC Berkeley's College of Engineering sums it up accordingly: "Biology is the nanotechnology that works" (Pescovitz 2004). Or as the Royal Society puts it in its report "Nanoscience and nanotechnologies - opportunities and uncertainties": "Where we can find self-replicating machines is in the world of biology" (The Royal Society 2004).

The difference between self-organization and self-replication is important - and long before the point, as here in this project, at which hopes are being placed in steps toward a sustainable economy based on nanotech-nologies using the principles of self-organization of molecules.47 Technologies based on principles of self-organization promise - already at the inorganic level (for example in the case of template-controlled formation of structures, directional crystallization, and the already mentioned SAMs) - reductions of material and energy needs as well as supervision and control expenses. Self-replication refers to the self-reproduction of which organisms are capable - including, for example, genetically altered organisms. Self-organization and self-replication are therefore very different "capabilities." Nonetheless, transitional states between them are entirely

47 And these are quite widespread expectations. See, e.g., the technology analysis of nanobiotechnology (VDI-Technologiezentrum 2002, S. 105f) The bottom-up synthesis of material structures, making technological use of self-organization phenomena, was singled out as particularly promising and a further technology assessment especially for this topic was recommended; with good reason in our opinion. In fact, this appeared in 2003 (see VDI-TZ 2003) and expressly underscored this potential.

possible. In the course of biological evolution, the capability of self-replication must, in fact, have developed - at least once - out of the self-organization function, of course, over an immeasurable period of time.

In a hazard or risk assessment with a view to advanced applications of self-organization (e.g. a combination, conversion, or merger of nanotech-nology and biotechnology, and perhaps also nanotechnology and robotics), the aspect of self-reproduction has a certain relevance that simply cannot be dismissed on grounds of technological (in)feasibility. The move from self-organization to self-reproduction certainly would bring with it new dimensions of risk.

As long as nanotechnology limits itself to the handling of inorganic molecules, such a step, from the self-organization of molecules to self-reproduction and multiplication of nano-devices - unless deliberately attempted - should be quite unlikely. However, in the case of a merger of nanotechnology with genetic manipulation of organisms capable of self-reproduction, such a step is entirely viable.

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