I would expect such a person as him/her to revert to Philosophy as an expedient alternative..
On the other hand, simple Denial of God would / could result in a belief in something like Buddhism..
He was very educated in philosophy, languuages, etc, but worse... he reverts under stress to theoretical mathematics, being a Ph.D in it (I am a Ph.D in Mechanical Engineering, by contrast). Thus, his rigid doctrinaire approach is his "comfort food" of logical argument, though I am sure he would classify me as equally doctrinaire in a different direction.
Interestingly, if one would ask, how could such a person trained in the rigors of logic come to such ridiculous conclusions, I eventually concluded (after many years) that it wasn't his (or my) logic that was flawed, but his starting premises... namely, this "serve the greater good" worldview. Given his different premises, the chasm of difference in logical conclusions could frequently be predicted in advance. And maybe, this premise difference that I refer to is exactly what you meant by him "reverting to philosophy." Very astute, if that is what you meant.
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