This paper focuses some aspects of a debate which took place between Donald Davidson and Jaegwon Kim, about the problem of causal efficacy of mental properties in the physical world. The most famous expression of davidsoniannon reductive physicalism, the argument of Anomalous Monism, was criticized by Kim, because it tries to harmonize two allegations that can´t coexist in a physicalist thesis, and have to be considered as incompatible from a physicalistpoint of view. The first of these allegations is theAnomaly of the Mental, whichdefines the mental as autonomous from the system of laws that rule physical phenomena. The second allegation is that mental events and human actions are part of causal flow of natural events. Anomalous Monism seems to be an epiphenomenalist thesis, because, in Anomalous Monism, anomaly of the mental rules out causal efficacy of the mental in physical world.