Wednesday, 12 June 2013

Imagining Itself (part IV: Describing Mental Imagery)

There is a long history to the belief that imagination is conducted through the use of mental representations and this can be traced back at least to the 4th Century BC Greek philosopher Aristotle who wrote: “whenever one contemplates, one necessarily at the same time contemplates in images.”  This view, that treats mental imagery as the straightforward equivalent of perceptual experience, persisted unchallenged for more than two millennia.

Perhaps the first person to record significant divergences in peoples’ accounts of mental imagery was Charles Darwin’s cousin: Francis Galton. Being credited as the inventor of that infamous form of data-gathering known as the questionnaire, Galton conducted the first ever survey of mental imagery in 1880. He notes that significant numbers of respondents make claims to the effect of: “If I could draw, I am sure I could draw perfectly from my mental image.” He continues:

I have little doubt that there is an unconscious exaggeration in these returns. My reason for saying so is that I have also returns from artists, who say as follows: ‘My imagery is so clear, that if I had been unable to draw I should have unhesitatingly said that I could draw from it.’

Sadly, instead of recognising these varied accounts as evidence of an underlying problem with the application of perceptual terminology to mental states, Galton draws the unremarkable conclusion that different people possess differing levels of mental-image-forming ability. In a later section he goes on to write:

There exists a power which is rare naturally, but can, I believe, be acquired without much difficulty, of projecting a mental picture upon a piece of paper, and of holding it fast there, so that it can be outlined with a pencil.

This is an extraordinary claim and it is difficult to fathom how Galton could believe such an ability to be "acquired without much difficulty" when it is patently obvious that artists are unanimously unable to exercise such prodigious skill. If it were easily acquired it would, no doubt, be taught in schools at an early age and years of disciplined observation would be unnecessary, not to mention paper, teachers’ salaries and students’ fees.

What continues to cause great confusion and significant variance in reports, is the difficulty we encounter when attempting to investigate or describe cognitive processes such as mental imagery via the terminology of perceptual experience. Mental imagery ‘feels’ like perceptual experience but, for the majority of people, it is nonetheless clearly distinguishable from it, at least in practical terms. However, as soon as we attempt to describe this difference we find ourselves unavoidably drawn to the use of such words as vividness, vagueness, haziness, realism, veridicality, verisimilitude, clarity, brightness etc, all of which derive from descriptions of phenomena available to our senses. This has led to the repeated error, amongst scientists and philosophers especially, not only of proceeding as if we were somehow possessed of sensory faculties capable of observing our internal states but also of treating mental states, and mental imagery in particular, as perceptible experiences.

“Ahh”, you say “But I can describe my mental imagery. I have mental images and I can see them clearly. How can this richness be explained if not by mental images?” Few people deny what we call mental images altogether but what is under serious question – especially since Ryle – is any similarity between what we describe as mental images and their public equivalents: pictorial representations. Theorists differ considerably in the degree to which they are prepared to entertain the possibility that thoughts (of which mental images are a form) are non-representational in nature. Many seem to agree that mental images are significantly unlike pictorial representations but that they nonetheless serve a similar functional role, and a representational one at that. Others agree that mental images are functional but that they are in no way representational.

Why should it matter? There are several reasons, with potentially profound consequences for both philosophy and science. Firstly, it is important that scientists conduct their investigations on the basis of correct premises otherwise their interpretations of the available evidence are, at best, likely to be overcomplicated and, at worst, entirely false. If Copernicus had not cast doubt upon the geocentric view of the universe then the progress of scientific understanding would surely have been greatly impeded and the explanations and calculations necessary to explain the misconception would no doubt have simply compounded the initial errors. If mental states do not utilise representations – as the vast majority of scientists believe they do – then science will very likely be struggling needlessly to make sense of the data it gathers in the same way that pre-Copernican astronomers once struggled to explain the bizarre trajectories of the planets across the heavens. The scientific investment in the assumption that our mental life is conducted through mental representations (“mentalese”) is so widespread that it is difficult to comprehend the repercussions if the underlying hypothesis turns out to be incorrect. Recent developments in the theory of embodied cognition suggest that the edifice of mental representations may well come crashing down sooner than its supporters might otherwise think.

Part V of this series of posts on the imagination looks at some of the confusion that has arisen through what is described as “meta-representation” and introduces a few theories of the functioning of human imagination and its intimate interrelationships with perception, memory and consciousness.


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