Final answer:
The identity thesis holds that mental states are identical to brain states and supports monism-materialism. It contrasts with dualism but is distinct from eliminative materialism, as it doesn't deny mental states but frames them as physical brain activities.
Step-by-step explanation:
The identity thesis maintains that mental states are identical to brain states, but this view is distinct from eliminative materialism which denies the existence of traditional mental states altogether. The identity thesis instead supports a version of monism-materialism, suggesting that mental processes are brain processes, and it eschews dualistic distinctions between mind and body.
In philosophy, the debate on how the mind relates to the body has been ongoing, with the identity thesis positing a specific perspective. This thesis contradicts dualism, which states that mental and physical states are fundamentally different substances, as famously posited by René Descartes. Conversely, the identity thesis asserts a monistic view where only physical substances exist, and all mental activities are accounted for by brain activity. The identity thesis differs from eliminative materialism in that it does not reject the existence of mental states but rather claims that these states are simply brain states described differently.
Modern neuroscience tends to support physicalist viewpoints by increasingly providing evidence that what was once attributed to a non-physical mind can be explained by brain activity. This perspective is also influenced by developments in quantum mechanics, suggesting that not all events are pre-determined, allowing for a degree of unpredictability in the relationship between brain and consciousness.