A causal power has the ability to affect something causally. Descartes questioned how the immaterial mind and the material body can interact causally. They either rely upon a world that is not causally closed, or physical indeterminism. The conscious experiences that accompany brain processes are causally impotent. Such causally looped events then exist in spacetime, but their origin cannot be determined. Scientific studies contradict the NoFap belief that pornography use and erectile dysfunction are causally linked. Strong emergence can be criticized for being causally overdetermined. They may disagree on the order of operations that are causally unrelated. Still, the DN model formally permitted causally irrelevant factors. However, whether isotretinoin use is causally associated with mental illness remains controversial. The result is that physical causes exclude mental states from causally contributing to the behavior. Poverty and infectious diseases are causally related. Compatibilists maintain that mental reality is not of itself causally effective. It is required that what the agent causes is not causally determined by prior events. Any possible world is causally and spatiotemporally isolated from any other possible world.