As Bostrom seems to realise, he has made a strong argument for positive trajectory changes, not only reduction of x-risk, although this is the most obvious kind.

Here's my interpretation of this post as a Venn Diagram. Discrete permanent changes are actions that changes the relative likelyhood of permanent future scenario like FAI, permanent global totalitarianism or annihilation. http://i.imgur.com/8TyxHXK.jpg

Accelerating economic development may be a (continuous) positive trajectory change, but it will very likely also bring forward existential risk from technology, a special kind of discrete trajectory change.