Saturday, 28 March 2015

The Mismeasure of Minds

In order to tell whether something is fixed, one needs something else that is known to be fixed and can serve as a criterion of judgement. But how can one find that first fixed point? We would like some nails in the wall to hang things from, but there is actually no wall there yet. We would like to lay the foundations of the building, but there is no firm ground to put it in.” —Hasok Chang (2009)
When we perform a skilful action like catching a ball, is it necessarily the case that the brain also performs a series of skilful measurements and calculations? Are our skills of perception and intelligent action evaluative? Many theorists confidently assert that they are. I aim to explain why I think such an assumption is both explanatorily extravagant and a hindrance to enquiry.

The word “calculate” derives from the Latin word "calculus", which once referred to the stones used as counters in abacuses. In standard usage, to calculate something is to determine a value by the use of various mathematical operations applied to quantities represented by symbols. It is possible to perform many calculations without the use of symbols, but the demands of doing so (i.e. the quantities involved), make non-symbolic calculation extremely unwieldy. Certainly we have no evidence of non-symbolic neural calculation even in the brains of simple creatures. So if it is the case that brains perform calculations, then they must be using a symbolic system to encode information. Although there is an enormous quantity of literature on the subject of neural encoding, as yet no code has been identified or unravelled. This alone should make us wary of neurocalculation.

Symbols are highly sophisticated entities. The Roman symbol “IX” bears no resemblance to the quantity it represents. Nor does the equivalent linguistic symbol “nine". Many people in the world who recognise "9" and "IX" do not recognise “nine”. Turn "9" and "IX" upside down and their corresponding quantities change. And if you say “nine” in Germany the meaning is not a number at all. It should be obvious even from these trivial examples that symbolic representation is far from straightforward. Neurosymbolic communication thus carries an extremely heavy explanatory burden. Why, for instance, would brains need symbols if they were already so advanced that they could develop their own symbolic system? As brains evolved, how did the parts that didn't know the code understand the parts that did? Why do we have no evidence of basic symbols amongst simple brains? And why are we denied access to the computational power of our own brains to such an extent that we have to sit through hours of instruction and practice to learn just a tiny fraction of what our brains are allegedly capable? None of these issues refutes neurocalculation but they do help to suggest that we have little reason to be confident about its credibility.

And what of neuromeasurement? 

In 2009 Hasok Chang published a book entitled: “Inventing Temperature: Measurement and Scientific Progress.” In it he provides a detailed history of the many complexities involved in arriving at a system for the measurement of temperature. It seems obvious to us now that water freezes at 0 degrees and boils at 100. But in fact the variables involved, like chemical impurities and atmospheric pressure as well as the fact that thermometers themselves had no standard measure, made the whole process an extremely challenging one, requiring numerous iterative improvements, insights and innovations.

Chang raises a significant obstacle for advocates of neuromeasurement. In order to measure an unknown distance for example, a standard would first be needed. But in order to establish a standard, a unit of measure would also be required. According to Chang: "This circularity is probably the most crippling form of the theory-ladenness of observation" and is the very problem that has caused well documented difficulties in every region of the science of magnitude.

One thing is certain, brains did not evolve their own inner form of science and technology. But if it took science and technology to enable the invention and refinement of our skills of measurement, then it seems extremely unlikely that brains could evolve similar techniques independently. 

Could there be such a thing as a set of evolved biological standards equivalent to those developed by culture? Are such standards actually necessary, or is there a more simple and plausible explanation for the many sophisticated skills we possess?

Imagine a single celled organism that consistently moves towards one sort of thing rather than another similar sort of thing. In that case we would say that the organism is capable of discriminating between these two similar things. Such differential responsiveness is a commonplace amongst organisms and makes up by far the greater proportion of all organismic behaviour. When the iris of the eye contracts in response to bright light as opposed to dim light or when the liver produces bile in response to fatty food as opposed to carbohydrate we do not suppose that any calculation is going on, nor any measurement. The organism is simply behaving in response the presence of one sort of thing rather than another. No choice is being exercised, no calculation, no judgement, no theorisation, no measurement, merely evolved responsiveness.

Certainly the processes involved in more sophisticated forms of responsiveness are of a higher order of complexity. But the fact of differential responsiveness gives us good reason to first explore the potential of this more fundamental form of sensory discrimination in the actions of sophisticated creatures long before we go attributing skills of neurocalculation and neuromeasurement to brains.

When a child discovers by chance that a stick can be balanced across their hand, is sensory discrimination sufficient to explain their capacity to balance the stick? I don't see why not. To be disposed to move the stick in one direction as opposed to the other in order to maintain its horizontal position would seem to be a far more straightforward answer than neurocalculation and neuromeasurement.

Skills like balancing sticks are comparative. They trade both on sensory discrimination and — crucially — its lack. To be disposed to respond to two things (or two parts of one thing, in this case) in the same way because we fail to discriminate between them in one or more respects has significant efficacy. To know how to make a stick balance across your hand is to know how to make one side of the stick behave in the same way as the other side. In essence the skill is based upon an ability to make one side of the stick match the other in respect of the forces acting upon it: to make both sides of the stick indiscriminable from one another in respect of their tendency to fall. From the point of view of artificial intelligence this is an extremely complex skill, but from a haptic point of view it is child's play.

Thanks to Jason Streitfeld for the FB discussion that led to this post.

Thursday, 19 March 2015

Acquisitions of Brain and Body

Like most adults I have a fair quantity of scars on my body, mostly on my hands. The majority of these marks and disfigurements are minor, nonetheless it often strikes me as surprising that so many of us manage to retain all of our fingers through life. Considering the many dangerous things we do with our hands, it is a testament to our skills and foresight (and no small amount of first aid and general hygiene) that our hands are often in such good shape.

We commonly speak of scars as acquisitions, as things we obtain through mishap and misadventure. Scars are additions, and sometimes, in the more extreme cases, evidence of subtractions from the body – from what we would otherwise have.

It is common also to speak of skills as acquisitions – as abilities we gain through practice and experience. Knowledge also, is a capacity we tend to think of as an acquisition.

To acquire something is to gain, or to form, a certain kind of possession, typically of an object or else a demeanour, attitude, disposition or tendency. In these latter cases the term “acquisition” is used in a technical sense that could just as easily be replaced with adopting an attitude, forming a disposition or developing a tendency.

In ordinary usage, acquisition most commonly pertains to objects or other forms of material wealth. To acquire a trophy is usually – trophy-scars notwithstanding – both to acquire an object as well as the admiration, acclaim or appreciation for which it stands. But to gain recognition is not actually to acquire anything so much as it is an increased likelihood to be treated preferentially by people in the know. It is very common for such social achievements to be recognised through the use of material tokens: trophies, epaulettes, titles etc.

So, like our less extreme scars, acquisitions are most commonly additions to what we already possess and whilst such possessions may take up little space, they do nonetheless need to be accommodated. Even digital information needs to be stored.

It is no surprise therefore that we tend to describe skills and knowledge in terms of content, as things we bundle away in our heads ready for later use. It’s as if our brains were vast repositories of information which we routinely access in the same way we retrieve books from a library or artefacts from a museum. If we acquire stuff, then it follows that we need somewhere to store it. And what better place than the brain? But what seems obviously the case is not necessarily the case.

Consider our hands again. When we learn to play the piano we do not speak of acquiring new additions to our hands. Our hands are not repositories. They do not store their capacities, even though they clearly have capacities, or at least they participate to a very large degree in the capacities of the person as a whole. When we learn a new technique requiring dexterity, we may develop the musculature of our digits etc. but there are no new hand acquisitions as such – not, of course, unless we inherit another scar or two. And if we are unfortunate enough develop carpal tunnel syndrome, arthritis or ganglion cysts these are not strictly speaking acquired – they develop or arise. The capacity was already there.

Many critics of the notion of mental content continue to speak of “skill acquisition” or “knowledge acquisition” as if there were no ground to be lost as a consequence. I’m not so sure the term helps us. In fact I think it may be a hindrance. Perhaps it would make more sense to speak of knowledge and skills in the same way that we regard the changes that occur in our hands when we learn a new technique. Perhaps we should make a point of regarding skills and knowledge as developmental changes rather than as acquisitions. You cannot acquire a development but you can develop a skill and you can develop your knowledge. Organisms and organs are things that develop. There is no room in a brain for any acquisitions. All the space is already taken. Knowledge and skills are develop-mental.