Feelings are biochemical mechanisms that all mammals and birds use in order to quickly calculate probabilities of survival and reproduction. Feelings aren’t based on intuition, inspiration, or freedom. They are based on calculation. When a monkey, mouse, or human sees a snake, fear arises because millions of neurons in the brain swiftly calculate the relevant data and conclude that the probability of death is high.
—Yuval Noah Harari, 21 Lessons for the 21st Century