Revision as of 17:23, 24 September 2009 edit Phantomsteve (talk \| contribs) Administrators 33,030 edits m Reverted edits by 198.200.132.69 to last revision by SmackBot (HG) ← Previous edit		Revision as of 17:27, 24 September 2009 edit undo 198.200.132.69 (talk) No edit summary Next edit →
Line 4: In [[philosophy]], the '''brain in a vat''' is an element used in a variety of [[thought experiment]]s intended to draw out certain features of our ideas of knowledge, reality, truth, mind, and meaning. It is drawn from the idea, common to many [[science fiction]] stories, that a [[mad scientist]] might remove a person's [[brain]] from the body, suspend it in a vat of life-sustaining liquid, and connect its [[neurons]] by wires to a [[supercomputer]] which would provide it with electrical impulses identical to those the brain normally receives. According to such stories, the computer would then be simulating a [[virtual reality]] (including appropriate responses to the brain's own output) and the person with the "disembodied" brain would continue to have perfectly normal conscious experiences without these being related to objects or events in the real world. ~~The~~Perhaps the simplest use of brain-in-a-vat scenarios is as an [[argument]] for [[philosophical skepticism]] and [[Solipsism]]. A simple version of this ~~runs~~may run as follows: Since the brain in a vat gives and receives the exact same impulses as it would if it were in a skull, and since these are its only way of interacting with its environment, then it is not possible to tell, ''from the perspective of that brain'', whether it is in a skull or a vat. Yet in the first case most of the person's beliefs may be true (if he believes, say, that he is walking down the street, or eating ice-cream); in the latter case they are false. Since, the argument says, you cannot know whether you are a brain in a vat, then you cannot know whether most of your beliefs might be completely false. Since, in principle, it is impossible to rule out your being a brain in a vat, you cannot have good grounds for believing any of the things you believe; you certainly cannot ''know'' them. This argument is a contemporary version of the argument given by [[René Descartes\|Descartes]] in ''[[Meditations on First Philosophy]]'' (which he eventually rejects) that he could not trust his perceptions on the grounds that an [[Evil Daemon\|evil demon]] might, conceivably, be controlling his every experience. It is also more distantly related to Descartes' argument that he cannot trust his perceptions because he may be dreaming (Descartes' dream argument is preceded by [[Zhuangzi]] in "[[Chuang Chou]] dreamed he was a butterfly".). In this latter argument the worry about active deception is removed.

Brain in a vat: Difference between revisions