In the Philosophy of Mind there are at least four distinct materialist positions all of which hold that mental events like thoughts are material (or brain) phenomena:

• Reductivism - all so called “mental” phenomena are reducible to a specific set of material events in the brain (usually thought to consist of a one-to-one correspondence between individual cognitions and specific neurons)
• Eliminativism - since all “mental” phenomena are really brain events, we should purge our language of all archaic mental terminology and replace it with a new neuro-physiological vocabulary
• Functionalism - all “mental” phenomena are brain events, but there is no one-to-one correspondence between cognitions and specific neurons in the brain; a systems approach to Reductivism
• Behaviorism - all so called “mental” phenomena are merely linguistic references to the tendencies of organisms (particularly humans) to behave in certain predictable ways to external stimuli

What each of these views shares in common is a rejection to the belief that the 'mind' or 'soul' is a metaphysical entity distinct from the body.