The mind is a non-physical substance. But how could a non-physical entity give rise to physical effects? Physical causation (one physical event causing another) is the only kind of causation known to us. Dualism is also incompatible with the practices of working psychologists which use experimental methods of the physical sciences: if mental processes were different in kind from the physical, how could physical experiments detect them?
(``Mind'' Nous was introduced by Anaxagoras of Clazomenae 500-428 B.C..)
Dualism in philosophy refers to the use of two irreducible heterogeneous principles (sometimes in conflict, sometimes complementary) to explain the knowing process (in epistemology - being and thought, subject and object, sense datum and thing), or some broad aspect of reality (in metaphysics - God and the world, matter and spirit, body and mind, good and evil).