- Explain Locke’s Causal Theory of Perception? What is it meant to explain? What relation does it bear to the Primary Quality/Secondary Quality distinction? Does his theory succeed? 2. Searle argues that the mind can be causally reduced to the brain but it cannot be ontologically reduced to the brain. Explain what he means by these two notions. Why, according to Searle, does the causal reduction fail to produce a corresponding ontological reduction in the case of the reduction of mental phenomena to brain phenomena? Is Searle correct? Why or why not?