Monism, Physicalism and Naturalism

In the philosophy of mind, monism is an answer to the mind-body problem, which holds that there is only one substance that exists, be it mind or body. The two main versions of the monist response to philosophy of mind are physicalism, which holds that only the body truly exists, and idealism, which argues that only the mind truly exists. The alternatives to monism are the various versions of dualism.

Physicalism is a position in philosophy of mind which argues that mental processes are the result of, or can be reduced to, physical processes in the brain. There are various forms of physicalism, but the position is generally a monist one, which holds that there is only one substance with a place in ontology: the physical.

Naturalism is the belief that nature is all that exists, and that all things supernatural (including gods, spirits, souls and non-natural values) therefore do not exist. It is often called Metaphysical Naturalism or Philosophical Naturalism or Ontological Naturalism...

It holds that any mental properties that exist (and hence any mental powers or beings) are causally derived from, and ontologically dependent on, systems of non-mental properties, powers or things (i.e. all minds, and all the contents and powers and effects of minds, are entirely constructed from or caused by natural phenomena). Some naturalistic beliefs claim that what is commonly called supernatural is, in fact, part of the natural world.