Long live the unreasonable man.

541 SHAW’S FAMOUS REMARK encapsulates more dimensions of my attitude to the crusade against aging than may be initially apparent. Here I will elaborate on three. In an equally well-known remark, St. Francis of Assisi is reported to have said (albeit, presumably, in Latin): “Lord grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference.” This aphorism is the mainstay of those who lean, in ethical and sociological matters and especially where new technology is concerned, towards the “precautionary principle”—the view that one must be rather confident that there are no significant drawbacks to a given policy before one embarks upon it. In less abstruse language, the precautionary principle might be termed “fear of the unknown,” and in my view that latter term describes it better, because it is indeed a fear rather than a principle: it is irrational. Moreover, its irrationality extends to the invocation of the St. Francis quote, because one is always wrong to conflate what should be done with what can be done. The situation is not as simple as I am proposing, of course. First of all, fear of the unknown—or, to be precise, behavior indistinguishable from fear of the unknown—is, to some extent, perfectly rational. Most people are emotionally predisposed to avoid the risk of adverse events even if that means also passing up a comparably likely opportunity for a comparably positive outcome; that preference is for present purposes axiomatic (i.e., something that does not require further justification). The problem arises when avoidance of such risks is taken to an extreme that exceeds the intensity of this preference,1 something that is most prone to occur when the probabilities cannot be accurately assessed. In Rumsfeldian terms, fear of the unknown becomes insidious only when it extends to fear of unknown unknowns; fear of known unknowns is not a fear but a choice. Moreover, it is perfectly possible to have irrationally little fear of the unknown. The philosopher Max More recently coined the term “proactionary principle” to denote the reciprocal of the precautionary principle, and the similarity of the two terms is apposite, because there is symmetry not only in the logic that underlies the acknowledgment that people do not like adverse events but also in the failure of logic that underlies the overinterpretation of that acknowledgment. A recently formed organization named the Lifeboat Foundation focuses on the most extreme risks facing humanity, especially those that could wipe us all out in one fell swoop; its work incorporates the evaluation of how to implement defenses against things that might happen if we do nothing (asteroid impacts, for example) with whether it would be advisable to prevent the development of certain technologies, such as recursively self-improving intelligent computers (a topic that is also the major focus of the more long-standing Singularity Institute). However, these caveats must not blind us to the fact that many of the most articulate commentators on the desirability of future technology exhibit unequivocally excessive fear of the unknown, on a scale that exceeds the rational. As an example, the eminent and widely respected bioethicist Daniel Callahan2 recently responded to one of my articles3 as follows: