Embodiment and the Inner Life

Cognition and consciousness in the space of possible minds

Murray Shanahan


Embodiment and the Inner Life (Oxford University Press, 2010) weaves together a number of themes from the philosophy of mind, cognitive psychology, and neuroscience, in an attempt to form a seamless theory of the mind and its place in Nature, a theory in which consciousness, cognition, and embodiment are all given their due. Here are eight of the bookÕs central ideas.

1. The lure of philosophy

How could human thoughts and feelings, the subjective, private character of a personÕs inner life, possibly be amenable to scientific explanation? IsnÕt there, ultimately, an unbridgeable metaphysical divide between our private selves and the physical world we inhabit? In his later philosophy, Ludwig Wittgenstein managed to escape from this dualistic way of thinking. But contemporary philosophers and scientists studying consciousness have largely neglected Wittgenstein, and Embodiment and the Inner Life seeks to put this right.

2. Embodiment

A complex environment affords an animal more possibilities for action than can be hard-wired into its brain. Embodiment and the Inner Life takes the stand that cognition is inherently embodied insofar as its fundamental role is to modulate an animalÕs sensorimotor interaction with its environment. Cognition does this by discovering new possibilities for action, either by experiment or through imagination, and introducing them into the animalÕs repertoire. It follows, according to the theory of the book, that an intimate link exists between cognition and consciousness. Specifically, the conscious condition facilitates the exploration of previously untried action combinations, which is especially beneficial in novel situations.

3. The space of possible minds

Given that it makes sense to approach consciousness using the scientific method, what sort of theory should we seek? Are we looking for a theory of the human mind, of consciousness in humans alone? If we are looking for a deep theory, something as potent as, say, the theory of evolution by natural selection in biology, then it must surely encompass other animals. Certain birds, notably rooks and crows, are capable of remarkably intelligent behaviour, even though their brains are organised quite differently from our own. The brain of an octopus, another cognitively precocious animal, is even more alien. Embodiment and the Inner Life articulates a high-level theory of cognition and consciousness that is not constrained by specific biological details.

4. The conscious condition

Much of our waking lives is devoted to habitual, automatic behaviour, such as driving or cleaning our teeth. But the episodes in our lives that matter to us most are those that we can remember, that we can talk about, that we respond to emotionally, the epsiodes that engage us fully, in short the conscious episodes. Building on the pioneering work of Bernard Baars, Embodiment and the Inner Life accounts for the distinction between automatic behaviour and the conscious condition in terms of a contrast between localised brain activity and globally integrated neural states in which the whole brain, indeed the whole person (or animal), is brought to bear on the ongoing situation.

5. Brain connectivity

How might the brain be organised so as to realise the globally integrated states that are hypothesised to be the hallmark of the conscious condition? According to Embodiment and the Inner Life, the key is to understand the pattern of long-range neural connections that constitute the brainÕs communications infrastructure. These connections enable information and influence from around the brain to funnel into a connective core, from where it can be broadcast back out again. Thanks to the structure of this connective core, which acts as a global neuronal workspace, a serial procession of thoughts is distilled from the activity of massively many parallel processes, and unity arises out of multiplicity.

6. Synchronised brain rhythms

Like waves created by raindrops falling into a pool from the many branches of an overhanging tree, the electrical activity of the brain displays exquisitely patterned interacting rhythms. Among these patterns, episodes of synchronised activity can be discerned at multiple frequencies, across widely separated sites. Drawing on recent findings in neuroscience, Embodiment and the Inner Life proposes that long-distance synchronised activity is a signature of the conscious condition, indicating that a coalition of brain processes is co-operating and communicating via the global neuronal workspace (connective core), to the exclusion of rival coalitions.

7. Fluid cognition

One hallmark of sophisticated cognition is the ability to respond to novelty by effectively recombining the elements of an established behavioural repertoire. In terms of neural dynamics, this amounts to the capacity to explore an open-ended repertoire of coalitions of distributed brain processes. According to Embodiment and the Inner Life, this is facilitated by the conscious condition, wherein new coalitions of brain processes can form thanks to the involvement of the global neuronal workspace, which allows channels of communication to open up between pairs of brain processes that are not already associated.

8. The inner life

An animalÕs interaction with the world can be thought of in terms of a loop: the animalÕs senses influence its actions, its actions influence the world, and the world in turn influences its senses. Embodiment and the Inner Life advances the notion that this outer loop is complemented by an internal sensorimotor loop, in which the arc from motor activity to sensory activity is closed within the brain itself. Thanks to this internal loop, an animal can rehearse possible actions before carrying them out. The dynamics that results when such the internal sensorimotor loop is combined with a global neuronal workspace is potent, and inaugurates the life of the imagination, as well as inner speech, reason, and reflection.