Causality in Neuroscience and Its Limitations: Bottom-up, Top-down, and Round-About

Abstract

Apart from the generally accepted concept of bottom-up causation there is increasing interest in elucidating particular phenomena suggesting top-down causation, especially in biology. It will be demonstrated, with examples from different levels of biological functions, that top-down causation cannot be a surprise as long as functional interrelations can be described in system-theoretical terms which, in biology, typically means in terms of feedback loops. In such systems bottom-up causation is always intermingled with top-down causation so that it might be more appropriate talking of circular or “round-about” causation. However, elucidation of causal relations in living systems is particularly complicated due to their specific features compared to physical systems or technical artifacts. Among them is the multiple meshing of a manifold of feedback loops with nonlinearities and time delays combined with intrinsic randomness. A particular challenge is the integration of mental and cognitive functions, touching the still unsolved of brain–mind problem.