The knowledge argument is an argument against physicalism, the view that the world is wholly physical. It was developed by Frank Jackson (1943–) and is based on the following thought experiment.
Everything that can be known through the physical, chemical, and biological sciences – the complete physical truth – has been discovered. Mary is a brilliant scientist who is raised in a black-and-white room. She has never had colour experiences. But she learns the complete physical truth, which includes the completed science of colour vision, by reading books and watching lectures on a black-and-white television monitor. Then she leaves the room and sees colours.
Jackson’s argument runs roughly as follows. When Mary leaves the room, she learns something new. She learns what it is like to see in colour. Evidently, the complete physical truth is not the complete truth about the world. Ergo, physicalism is false.
Some react by denying that Mary learns anything when she leaves the room. Others react by accepting that she learns something but denying that this refutes physicalism. Still others accept the argument as sound. The ensuing discussion has led to a variety of insights about consciousness and its place in the natural world.
Phenomenal Consciousness: A Critical Analysis of Knowledge Argument, Inverted Spectrum Argument and Conceivability Argument
