I have not read Pinker’s book, so my response here is speculative. But there are two issues that appear problematic in that sort of analysis.

First, people often pick assumptions on an emotional basis, regarding, for instance, values. That means that there is no sharp distinction between an emotional and a rational approach.

Second, and related, neuroscientific research (e.g., Damasio) clearly shows that a clear distinction between emotions and reason simply does not map on how the brain actually works. All thinking is both emotional and cognitive.