original_query: What is the conclusion of the critical discussion regarding 'downward causation'?
query: What is the conclusion of Popper's critical discussion regarding 'downward causation'?
answer: Popper argues that critical discussion favors the conclusion that 'downward causation' (mental states/processes changing physical brain states/processes) occurs, even though the mechanism is unknown.  This is supported by the evolutionary rationale for the development of mental capacity, which would be inexplicable without mental states causally impacting behavior and survival.