Homo Deus: A Brief History of Tomorrow

by Yuval Noah Harari

These are not just hypotheses or philosophical speculations. Today we can use brain scanners to predict people’s desires and decisions well before they are aware of them. In one such experiment people are placed within a huge brain scanner, holding a switch in each hand. They are asked to press one of the two switches whenever they feel like it. Scientists observing neural activity in the brain can predict which switch the person will press well before the person actually does so, and even before the person is aware of their own intention. Neural events in the brain indicating the person’s decision begin from a few hundred milliseconds to a few seconds before the person is aware of this choice.2 The decision to press either the right or left switch certainly reflects the person’s choice. Yet it isn’t a free choice. In fact, our belief in free will results from faulty logic. When a biochemical chain reaction makes me desire to press the right switch, I feel that I really want to press the right switch. And this is true. I really do want to press it. Yet people erroneously jump to the conclusion that if I want to press it, I choose to want to. This is of course false. I don’t choose my desires. I only feel them, and act accordingly.

Free wil test