For hundreds of millions of years before the recent emergence of reason, evolution elaborated a multiplicity of ways of knowing through feelings, which remain valid today. Each way of knowing, including reason, is mediated by a ‘mental organ’ which is a population of neurons bearing a particular neurotransmitter receptor (e.g. serotonin-7, histamine-1, alpha-2C). Each mental organ adds spice to our lives. Reason coevolved with a pre-existing affective domain, and is designed to be informed by affective input. When reason reigns at (...) the cost of losing touch with the other ways of knowing, we retain the ability to manipulate nature, but we do not understand its essence and cannot make wise judgements. (shrink)