242 CHAPTER 12 The Impact of Nanotechnology Nano-engineered "artificial kidneys" can be used not only to extract desirable ele- ments from very dilute sources, such as seawater, but also to extract harmful elements or extractable compounds from natural water polluted with them. 12.6 SOCIAL IMPLICATIONS The focus in this section is on some of the collective activities of humankind, those that have not been covered in the preceding sections. Clearly the technical advances sketched out in Section 12.3 also have social implications; for example, local- ized medicine--diagnosis and treatment--will make large central hospitals obsolete, which will be quite a big social change. If the present commercial model becomes obsolete, what are the political implica- tions? The political arrangements in most countries have co-evolved with commercial developments. If centralized production becomes obsolete, does that imply the same for centralized government? 12.6.1 Regulation There are already widespread calls for stricter regulation of the deployment of nano- technology, particularly nano-objects in consumer products. These calls are driven by a growing awareness of the potential dangers of nano-objects penetrating into the human body, and by the realization that understanding of this process (cf. Section 4.3) is still rather imperfect, and prediction of the likely effects of any new kind of nano- object is still rather unreliable. Furthermore, there have been a sufficient number of cases, albeit individually on a relatively small scale, of apparently unscrupulous entrepreneurs promoting nano-object-containing products that have turned out to be quite harmful. These calls, while seemingly reasonable, raise a number of difficulties. One is purely practical: once nano-objects are incorporated into a product they are extraor- dinarily difficult to trace. Traceability is only feasible up to the point of manufacture, and even then only if the manufacturer has sourced materials through a regulated or self-regulated commercial channel such as a commodity exchange. Establishing the provenance of nanoparticles that might turn up in a waste dump, for example, poses a very difficult forensic challenge. Furthermore, regulation will become essentially meaningless if productive nano- systems become established: every individual would be producing his or her own artifacts according to his or her own designs and it is hard to see how this could be regulated. 12.6.2 Military Implications It is a striking fact that the mechanization of war has resulted in a reversion of soci- ety's involvement in fighting to an early epoch when every member of a tribe was essentially a warrior. During the last 3000 years, the trend in civilized countries was