This is a linkpost for http://curi.us/2065-open-letter-to-machine-intelligence-research-institute
That isn't even a philosophy book. And then you mention others who are doing math, not philosophy.
You could say that a lot of philosophers who dealt with logic where just doing math, that doesn't change anything about practical application of logic being important philosophically. Looking into what can be proven to be true with logic is important philosophically.