William James was an acknowledged master of phenomenal description. He gave us the "stream of consciousness" that "flows," and the newborn's mental life as a "blooming, buzzing confusion." But in Consciousness Is Motor, Alexander Klein shows that James sculpted these phenomenal descriptions around an armature of empirical details. His book reconstructs James's models of consciousness and volition, uncovering results from animal experimentation and clinical observation on which those models were built. What emerges is a more powerful and more empirically-informed account of mind than has been appreciated.

James's early work on consciousness engaged the 1870s automatism controversy. The controversy was triggered, Klein argues, by experiments demonstrating that living, decapitated frogs are capable of goal-directed action. One side regarded goal-directedness as evidence of spinal consciousness; the other espoused epiphenomenalism, reasoning that consciousness must play no role in producing even purposive action since the latter is possible for brainless creatures.

James intervened, Klein shows, by arguing that consciousness has a likely evolutionary function-behavior regulation-and so cannot be a mere epiphenomenon. It accomplishes this function by affording a capacity for evaluation, on Klein's reading. As evidence, James appealed not just to introspection, but also to experimental facts, such as that hemisphere-less vertebrates have a diminished capacity for evaluating different available means to pursue goals. James's "ideo-motor" model of action demonstrated precisely how an evaluating consciousness could help regulate behavior. Klein excavates key clinical observations James designed the ideo-motor model to accommodate, including observations of patients with impairments like paresis and anaesthesia. The resulting model features an early example of a predictive, error-correction feedback loop for motor control.

Klein concludes by showing how James's models of consciousness and action feed into his distinctive philosophical outlook, soon to be known as pragmatism. According to his doctrine, meaning and truth are understood in terms of goal-directed action guidance. Consciousness Is Motor paints a striking new portrait of James as an empirically-informed philosopher and psychologist-one who anticipated some contemporary approaches, even while furnishing neglected alternatives to theoretical problems that continue to vex researchers today.