Book Review: Contemporary Sensorimotor Theory

Consciousness, with its irreducible subjective character, was almost exclusively a philosophical topic until relatively recently. Today, however, the problem of explaining the felt quality of experience has also become relevant to science and engineering, including robotics andAI: “What would we have to build into a robot so that it really felt the touch of a finger, the redness of red, or the hurt of a pain?” (O’Regan, 2014, p. 23). Yet a practical response still requires an adequate theory of consciousness, which brings us back to the hard problem: how canwe account, from a scientific point of view, for the phenomenological character of experience? Over a decade ago, O’Regan and Noe (2001) proposed a new approach to these questions, the so-called sensorimotor approach to perceptual experience. How far has this approach come and what are its outstanding challenges? The volumeContemporary Sensorimotor Theory, edited by Bishop and Martin, takes stock of the current state of the field. The book starts with Bishop andMartin (2014) presenting different facets of sensorimotor theory, highlighting, for example, that O’Regan (2011) and Noe (2004) ended up developing different ideas concerning the applicability of the theory to robots: a positive account appealing to higherorder cognitive capacities versus a skeptical stance citing the necessity of life for mind, respectively. Ambiguous labeling does not help the current situation. According to Hutto and Myin (2013), the sensorimotor approach of O’Regan and Noe (2001) is also “enactive,” a label which Noe (2004) himself began to adopt, but from which Pascal and O’Regan (2008) distanced themselves. In fact, several overlapping approaches may be distinguished in addition to the classic sensorimotor approach, including sensorimotor enactivism (Varela et al., 1991; Noe, 2004), which turned into autopoietic enactivism (Thompson, 2005, 2007; Noe, 2009; Froese and Di Paolo, 2011), and which is distinguished from radical enactivism by Hutto and Myin (2013). The book’s contributions range over all of them. Noe did not contribute to this volume, but his absence is compensated by other submissions. Pepper (2014) points out some conceptual difficulties with Noe’s theory of perception, which could be resolved withMerleau-Ponty’s phenomenology of the body schema and sedimentation.Wadham (2014) claims that Noe’s theory implies the invisibility of perspectival properties, which requires a revision of his theory of perspectival content. O’Regan (2014) reports on his sensorimotor approach. He proposes that “experiencing a sensation involves being engaged in sensorimotor interaction” but that “being conscious of something [. . .] requires appeal to a form of ‘higher-order’ cognitive access” (p. 34). In contrast, Rainey (2014) argues that consciousness is non-conceptual while experience is conceptual, and that consciousness is, therefore, the enabling ground for the possibility of experience.