Source: 📖 21 Lessons for the 21st Century ch3

Feelings are not the opposite of rationality, they are evolutionary rationality

We often consider feelings and rationality to be dichotomous phenomena, but in fact feelings arise from biochemical calculation passed down through the genetics of our ancestry. When a monkey sees a snake and feels fear, that is a biochemical algorithm in its neurons evaluating the present danger to be extremely high. When sexual attraction is felt, that is another biochemical algorithm evaluating that there is a chance for mating. Data is taken in, processed, and the output is an emotional response that catalyses behaviour. These emotional responses were honed over millions of years of evolution and the most successful responses for the environment passed down to us—if an ancestor's feelings made a mistake, they likely paid for that mistake and their lineage ended there.