Emotion is not a decorative element layered on top of cognition. It is a fundamental component of reasoning itself.
I recall a striking case in neuroscience that illuminates this point. A man suffered a stroke or some kind of injury that damaged the part of his brain responsible for emotional processing. What made the case remarkable was that he retained almost every other faculty. He could speak fluidly. He could solve puzzles. On tests of intellect, he performed well. By many conventional measures, nothing seemed fundamentally wrong. But he no longer experienced emotion. Not sadness, not anger, not excitement—nothing.
The surprising consequence was that he became incapable of making decisions. Even trivial choices consumed him. Picking out socks could take hours. Financial choices were disastrous. His life, once coherent, collapsed into paralysis. The lesson is not subtle. Emotion is not a decorative element layered on top of cognition. It is a fundamental component of reasoning itself. It serves as a kind of compressed value function, a fast and intuitive way of ranking possibilities, navigating uncertainty, and interpreting outcomes.
Without it, the machinery of choice breaks down. An organism that waits for pure logic to settle every decision would not survive long enough to reproduce. Evolution solved this by embedding coarse, powerful value systems in us—fear, pleasure, discomfort, anticipation, attraction. These signals are not precise, but they do not need to be. Their purpose is to move us.