Abstract

In this paper, we explore the architecture of downward causation on the basis of three central cases. We set out by answering the question of how top-down causation is possible in the universe. The universe is not causally closed, because of irreducible randomness at the quantum level. What is more, contextual effects can already be observed at the level of quantum physics, where higher levels can modify the nature of lower-level elements by changing their context, or even creating them. As one moves up through higher levels, contextual effects on lower levels occur on various scales within nature, which is crucial in biology in general and the brain in particular. We then argue that there are important logical downward causes.objects have causal effects on material-energetic systems. It can be shown that abstract objects have measurable effects on lower levels, which needs to be accounted for by successful explanations of real phenomena such as intentional action. Intentional action has the form of deductive causation from logical structures to human agency. Without this assumption, we would not be warranted in believing that our physical theories latch onto a universe that is essentially the way we discover it to be. Denying top-down causation on account of the idea that the universe permits only bottom-up constitution of wholes from lower-level elements leads to undermining the very possibility of knowledge and science. Thus, it can be rejected as a global form of explanation. We sketch a model for mind-body interaction according to which the various levels of a human organism together enable the emergence of mental top-down effects. They are necessary conditions for the emergence of human mindedness. Once it is clear that downward causation is a widespread natural phenomenon, the apparent mystery of mental causation is, in principle, solved.