People should be wary of those who quote which author?
From episode 16 - The Gates Of Judgement (at around 16:10), Shogo Makishima said:


  Justice is subject to dispute; might is easily recognized and is not disputed. So we cannot give might to justice,


In return, Shinya Kogami replied:


  I have long since learned, as a measure of elementary hygiene, to be on guard when anyone quotes Pascal.


So the answer is Blaise Pascal.

By the way, Kogami's reply is actually a quote from Toward a Philosophy of History by José Ortega y Gasset.