Criticisms of Dualism

Descartes argument for dualism I can clearly and distinctly conceive of the mind without the body and the body without the mind If I can clearly and distinctly understand two things as distinct they really are distinct. Therefore the mind and body are two distinct things.

The mind is characterized by one sort of property, thought Physical things are characterized by another sort of property, extension. Two different kinds of things understood in terms of two radically different kinds of properties

The Mind Body Problem If mind and body are really share no properties in common, then it is impossible for them to interact. But mind and body do interact Therefore Descartes’ substance dualism is false

Another mind/body problem It is a law of nature that matter and energy can be neither created or destroyed But if the mind causally interacts with the body, there is some new energy that comes into existence when the mind causes the brain to be in a certain state So interactionist dualism violates a fundamental principle of science

Substance and property dualism Substance dualism: two different things, mind and body Property dualism: Only one kind of thing, but human beings and animals have certain properties that are not physical— mental properties

Kinds of property dualism Epiphenomenalism: mental properties are byproducts of the physical body. They are caused by brain processes, but do not cause physical states. Its like smoke coming out of a locomotive engine. Interactive property dualism: mental properties do have causal effects on the brain

Emergence and non-reducibility Property dualism holds that mental properties are emergent properties When organisms reach a certain degree of complexity, they get mental properties Property dualism also holds that mental properties are non-reducible. You cannot understand the nature of mental properties by appealing to physical properties

Examples of Emergence Biological properties are emergent on chemical properties. Being solid is emergent on the properties of lots of of molecules and their interactions, same with being colored. But each of these are reducible. You can understand, for example, how a living cell works in terms of the chemical processes in that cell.

Do mental properties have to be emergent? Churchland: mental properties could be like electromagnetic properties. A different part of nature not reducible to others. But electromagnetism is displayed on all levels of reality, mental properties are only in complex organisms. How do we know this?

Panpsychism A property dualism might insist there are mental properties all the way down. This would make the emergence of conscious beings more comprehensible But it would also involve the belief that mental properties exist in so-called inanimate things.

The introspective argument for dualism Descartes held that because thinking, reasoning, mental processes seem to be distinct from physical states, they really are. Churchland argues that this may not be so. Colors don’t seem to be a matrix of molecules reflecting light, warmth does not feel like molecules vibrating.