Review of Sean A. Spence, The Actors Brain: Exploring the Cognitive Neuroscience of Free Will~1

摘要

Traditional philosophical accounts of free will have attempted to explain how human agents can choose and act freely in spite of divine foreknowledge and causal determinism, the thesis that natural laws and past events jointly determine a unique future. Neuroscientific findings in the last 30 years have shifted the focus of the debate on free will from these external factors to the internal relation of our brains to our minds. They have questioned whether unconscious mechanistic or deterministic processes in the brain can provide a complete explanation of human behavior without any appeal to the conscious mental states we associate with free will. In The Actor's Brain: Exploring the Cognitive Neuroscience of Free Will, psychiatrist Sean Spence perceptively analyzes and discusses this question by explaining the neuroanatomical and neurophysiological underpinning of human behavior, as well as how the brain interacts with environmental, genetic, and psychological factors in shaping the capacity to choose and act. Defining free will as volition, or unimpeded human action, Spence's general position is that these factors constrain the will to varying degrees: "The human capacity for volition, for voluntary control, or the apparent expression of 'willed' actions, is subject to multiple constraints" (363). He adds: "If the human agent possesses any 'freedom' at all, then it is a freedom that is expressed under certain 'optimal' conditions, be they structural, neurochemical, interpersonal, or situational. Phenomenologically, we certainly give the impression of being free, some of the time, but there are a great many circumstances that may serve to deprive us of such freedom" (378).