How can we trace out the links between actions that people take today and really long-term outcomes for humanity - outcomes that stretch out indefinitely into the future? I call this effort macrostrategy - that is, to think about the really big strategic situation for having a positive impact on the long-term future. There's the butterfly effect: A small change in an initial condition could have arbitrarily large consequences.
Nick BostromFor healthy adult people, the really big thing we can foresee are ways of intervening in the ageing process, either by slowing or reversing it.
Nick BostromOur approach to existential risks cannot be one of trial-and-error. There is no opportunity to learn from errors. The reactive approach - see what happens, limit damages, and learn from experience - is unworkable. Rather, we must take a proactive approach. This requires foresight to anticipate new types of threats and a willingness to take decisive preventive action and to bear the costs (moral and economic) of such actions.
Nick Bostrom