Physicalism is a contingent thesis, taken as true on the basis of strong inductive evidence and an inference-to-the-best-explanation that specifies it as the best theory over any of its competitors to provide an ontological account of the universe.

Why dualism is true?

The first reason why I think substance dualism is true is that all conscious individuals have an immediate and direct awareness that they are not identical with a material body or a bundle of mental events, but that they are "a seat of consciousness" that possesses a body and experiences mental events.

What is the causal argument for physicalism?

The causal argument in favor of physicalism roughly states that all physical effects are due to physical causes, hence anything having physical effects must itself be physical (cf. Papineau 2002).