Neid says economic growth---that’s an impact filter.

It follows from these observations that one could remove the correlative conjunction in the lexicographic definition and reconstruct it more succinctly as follows: ‘An event X is an existential risk if and only if X could permanently prevent humanity, broadly defined to include some possible posthuman descendants, from attaining a stable state of technological maturity.’ This is the essence of Bostrom’s first definition: the ultimate goal of civilizational development should be producing mature technology in a sustainable manner, so any event that prevents this from happening must be avoided at all costs.

This definition handles Scenario 1 from above without difficulty. As Bostrom (Citation2013) writes, ‘the permanent foreclosure of any possibility of this kind of transformative change of human biological nature may itself constitute an existential catastrophe.’ Bostrom also suggests that all four scenarios – and thus both disjuncts – are ‘of comparable seriousness, entailing potentially similarly enormous losses of expected value.’ Once again, this contrasts with the second definition in which the second disjunct has far less severe moral implications than the first disjunct, given certain assumptions.

But there are several problems with this definition as well. First, consequentialism is a minority view among philosophers, with only 23.6% accepting it as of 2013 (Bourget and Chalmers Citation2014). And, of course, not all consequentialists are utilitarians, just as not all utilitarians accept the aggregative and impersonal perspectives of the total view. Rather, some hold that there is a diminishing marginal value to creating new people, that the value of future lives is less than the value of current lives (temporal discounting), or that failing to create extra people isn’t bad even if those people would live extremely happy lives, since acts can only be bad if they are bad for someone (the person-affecting intuition). According to the latter view, Parfit is wrong to argue that the difference between 99% and 100% of humanity dying out is far greater than the difference between 1% and 99% dying out. Since the failure to bring into existence a potentially astronomical number of future people with worthwhile lives harms no one, human extinction is worse than the loss of 99% of humanity by only one percentage point. Note also here that the total view engenders the Repugnant Conclusion and violates the intuition of ‘procreational asymmetry,’ which implies, in slogan form, that we should focus on making people happy rather than making happy people.

Second, many would likely object to the transhumanist values that Bostrom imports into his definition. Bioconservatives, for example, oppose ‘enhancive’ modifications to the human phenotype, especially modifications that would alter our ‘human essence’ – what Francis Fukuyama (Citation2002) terms ‘Factor X’ – upon which liberal democracies are founded. But even some techno-progressives might find the emphasis on technological maturity off-putting: It could be seen as too crass, technocratic, ecologically exploitative, capitalistic, colonialist, and so on. The present author, in fact, knows of several scholars who balk at the lexicographic definition for precisely this reason. This is worrisome because it could lead such individuals to reason as follows: ‘Since existential risks are scenarios that prevent the attainment of technological maturity, and since I don’t care about subjugating nature, maximizing economic productivity, etc., it follows that I must not care about existential risks.’ The same could be said about the transhumanist desideratum of exploring the posthuman realm: why is failing to radically enhance the human species so undesirable? There are also issues relating to personal identity that arise in this context: it could be that the transformations required to become posthuman result in a genuinely new person, in the metaphysical sense (see author). From this perspective, the true risk is that everyone would essentially commit suicide by augmenting their brains and bodies.