Mental events enter into causal relations with bodily events. The philosophical task is to explain how this is possible. Descartes’ dualism of mental and material substances ultimately founders on the impossibility of pairing mental events with physical events as causes and effects. This is what I have called “the pairing problem.” Many contemporary views also fail to explain mental causation. In the end, we are left with a dilemma. If mental phenomena are irreducible to physical phenomena, then mental phenomena lose (...) their causal efficacy. However, if mental phenomena are reducible to physical phenomena, then casts doubt on the very existence of mental phenomena. (shrink)