V.S. RAMACHANDRAN in The Edge:
Freud once pointed out that the history of ideas in the last few centuries has been punctuated by “revolutions,” major upheavals of thought that have forever altered our view of ourselves and our place in the cosmos. First, there was the Copernican system dethroning the earth as the center of the cosmos. Second was the Darwinian revolution; the idea that far from being the climax of “intelligent design” we are merely neotonous apes that happen to be slightly cleverer than our cousins. Third, the Freudian view that even though you claim to be “in charge” of your life, your behavior is in fact governed by a cauldron of drives and motives of which you are largely unconscious. And fourth, the discovery of DNA and the genetic code with its implication (to quote James Watson) that “There are only molecules. Everything else is sociology”.
If all this seems dehumanizing, you haven’t seen anything yet. Consider the following thought experiment that used to be a favorite of philosophers (it was also the basis for the recent Hollywood blockbuster The Matrix): Let’s advance to a point of time where we know everything there is to know about the intricate circuitry and functioning of the human brain. With this knowledge, it would be possible for a neuroscientist to isolate your brain in a vat of nutrients and keep it alive and healthy indefinitely. Utilizing thousands of electrodes and appropriate patterns of electrical stimulation, the scientist makes your brain think and feel that it’s experiencing actual life events. The simulation is perfect and includes a sense of time and planning for the future. The brain doesn’t know that its experiences, its entire life, are not real.
Further assume that the scientist can make your brain “think” and experience being a combination of Einstein, Mark Spitz, Bill Gates, Hugh Heffner, and Gandhi, while at the same time preserving your own deeply personal memories and identity (there’s nothing in contemporary brain science that forbids such a scenario). The mad neuroscientist then gives you a choice. You can either be this incredible, deliriously happy being floating forever in the vat or be your real self, more or less like you are now (for the sake of argument we will further assume that you are basically a happy and contended person, not a starving pheasant). Which of the two would you pick?