Imagining Itself (Part VI: Noë’s Arc)

If what we call “mental imagery” does not consist of images and if unconscious mental processes are not conducted through the use of representations then what alternative theory might explain the workings of our most poorly understood organ. How can it be the case that we can remember huge tracts of information, faces, names, places, flavours, smells etc. unless the brain stores some kind of record, albeit a fallible and partial one, of the things we encounter? From where does our prodigious ability to remember, describe, calculate, think and respond to the world arise? And how is it possible that some individuals possess inordinate capacities to recall sequences of numbers, recite epic stories verbatim or to draw photorealistic images from memory if they are not using some form of mental inventory or image? Surely representationalism (to use the jargon) is inevitable.

In setting out his “Enactive Theory of Perception” contemporary philosopher of perception Alva Noë writes:

“A second implication of the enactive approach is that we ought to reject the idea - widespread in both philosophy and science - that perception is a process in the brain whereby the perceptual system constructs an internal representation of the world. No doubt perception depends on what takes place in the brain, and very likely there are internal representations in the brain (e.g., content-bearing internal states).” (2004)

Noë is attempting here to establish perception as wholly independent of mental representations; of images projected onto a notional neural screen carefully concealed somewhere inside our heads. Effectively he is rejecting the homunculus fallacy, and with very good reason. However, despite his reassuring rejection of representationalism in perception, Noë ends up resurrecting the very homunculus he has attempted to expunge. In stating that “content bearing internal states” are “very likely”, Noë makes it clear that he conceives of the brain as a kind of elaborate container in which representational content is housed.

Once again we face a difficulty posed by the commonplace linguistic metaphors used to describe the mind and we must be wary that these do not obscure or exclude other models of mind and mental processing that might offer equally plausible, if not superior, routes to an understanding of the workings of the brain. We are all familiar with metaphors that describe the brain as some form of container, some highly sophisticated but lossy neural bucket in which we dump all of our knowledge and experience, a repository, library, archive, hard drive, black box, recording device, etc. in which memories and information are stored for future use. But are these container metaphors the only possible way of conceiving of how the brain enables us to do all of the astounding things of which we we are capable?

In order to answer this question it might be helpful to return momentarily to Eric Kandel’s sea snails mentioned previously. In his Nobel prize winning work, Kandel demonstrated that sea snails respond to repeated negative environmental stimuli by synthesising proteins in their neural structures which then stabilise and reinforce their responses to further stimuli of a similar kind. In this way they become disposed to behave in certain ways in response to certain environmental triggers. The neural changes do not constitute a representation and no representation is necessary for them to respond. All that is necessary is an acquired disposition to respond in a certain way to a certain stimulus.

This notion of a non-representational dispositional theory of mind is most closely associated with the work of the British philosopher Gilbert Ryle who, in his 1949 book “The Concept of Mind”, put forward what has since become known as Analytical Behaviourism. Analytical Behaviourism argues that complex behaviours (those most commonly associated with the mind and mental states) are a result of the acquisition and implementation of dispositions to act. Just as sea snails acquire dispositions to behave in certain ways in response to environmental stimuli, so too do more complex organisms (human beings included). Obviously, as organisms become more sophisticated and the factors affecting them become more varied they must develop increasingly sophisticated mechanisms for dealing with the complex choices they face, yet the underlying processes of stimulus and response demand no functional assistance from representations or “mental content” (at least not in the way that mental content is most often conceived).

When asked earlier this year about the difference between organisms that merely react and organisms that perceive and purposefully act, Alva Noë responds:

“That is the anxiety that people have. You see that in Jason Stanley’s book, that I mentioned earlier. He seems to be worried that if propositional knowledge [i.e. knowing that as opposed to knowing how] doesn’t govern, then there’s no difference between us and mere reflex systems. I don’t share the anxiety however, partly because I’m much less disturbed at the thought that the bacterium has a primitive mind. It seems to me that we are on a spectrum with the bacterium.” (source 42mins in)

Can it be true that we are on a spectrum with the bacterium and the sea snail? Are perceptions and purposeful actions really just sophisticated forms of response or is there a fundamental conceptual difference that marks a clear evolutionary divide between responses on the one hand and perceptions on the other?

In K.T. Maslin’s 2001 entry-level book “An Introduction to the Philosophy of Mind”,  Maslin devotes a chapter to a discussion of the Analytical Behaviourism of Gilbert Ryle and others. In it Maslin asks students to consider the difference between the following two statements:

(a) Martin raised his arm. 

(b) Martin’s arm went up.

He goes on to distinguish between what he calls “agential descriptions” (i.e. purposeful actions and intentional deeds) and “colourless bodily movements.” Implicit in Maslin’s comparison is a recognition of a fundamental difference in kind between mere responses and intentional actions, a difference that makes little sense when explained as a spectrum with bacteria at one end and human perception at the other.

Responding to causal influences is straightforward – we can create robots to do this. We can even build computers capable of defeating the most expert of chess players. But to act purposefully, to anticipate outcomes and to form intentions requires something quite different, something that the engineers of Artificial Intelligence continue to struggle to achieve, something that eludes even the most colourful movements or sophisticated reflex systems. What is this special something? Imagination.

Imagination anticipates the future and uses this to guide actions in the present. But how could such a sophisticated predictive capacity have evolved? The evolution of human imagination will be the focus of the next three posts.