Imagine scientists have mapped out the pleasure centers of the brain, so they know exactly which brain cells “fire” when you experience the pleasure associated with eating and drinking, exercise, sex, etc. Suppose further that the scientists can insert electrodes into your brain and stimulate those brain cells in such a way that it feels exactly like you were experiencing the real thing. They tell you that you can stay attached to electrodes as long as you want. Do you think this would be a desirable life? (This experiment has actually been done with rats, and the rats consistently choose electrode stimulation, even if it means forgoing food.)