 In more recent decades two closely related strands of debate have focused on the nature of reduction, one within the philosophy of science and the other within the philosophy of mind. Philosophers of science have proposed several explications of the notion of reduction, often with an eye on broader conceptions of explanation, scientific change, and unification. Philosophers of mind concerned with specific questions about whether the mental just is physiological or even physical in nature have asked what notions of reduction might be relevant and how they might apply to particular cases in psychology and neuroscience. The former philosophy of science strand is the topic of  section 2,  and the philosophy of mind debate is discussed in  section 3.