Lecture 22: Ontology at the Ecological Scale (Turvey, 2019, Lectures on Perception)

After a book length set of preliminaries, we are finally getting to the meat of the positive case the ecological approach has to make. That case of course sits on top of a rejection of the Cartesian ontology that has been driving everything else; this chapter describe the first part of the ecological replacement, specifically affordances. 

An ecological ontology has to live up to several things we have established along the way:

1. No dualisms, only dualities. Dualisms entail two different kinds of things trying to relate, dualities are about mutual, complementary things trying to relate. 
2. Perception is about how the organism can possibly get about in it's environment (where organism and environment are a duality)
3. This requires prospective control
4. There are no thing-less properties, or property-less things; no space as abstract container or time as where that container lives. There are only propertied things, dual pairs.

Affordances of the environment, and the complementary effectivities of the organism, are how this duality plays out at the ecological scale for a perceiving-acting organism. Affordances and how they work are central exemplars of the ecological ontology. 

Affordances are dispositions; actions made possible by what things are and what they are made of. Affordances are properties of the environment; they reside in the layout of surfaces, etc. But they are, in Gibson's famous phrase, neither subjective nor objective properties. Instead they are something else; they are defined impredicatively (Lecture 3) across the organism-environment system. This does not make them relations (at least, not until they are being manifested). They are 'properties of the world such that their empirical content is always given by their mode of manifestation' (Harré, 1997); they are revealed when action happens. 

Turvey reviews some of the formal terminology for describing such things (see Turvey, 1992). But the practical upshot is that affordances are 'objective, real, and physical (but in a non-classical sense)'. With respect to the list at the start (in reverse order)

1. Affordances exist, and are actual properties, and are properties of things in the environment; they are impredicative, however.
2. Because they are about what is possible, not what is currently happening, they enable prospective control.  
3. They are about how the organism can organise it's effectivities so as to get around the world, and are perceived as such
4. Their impredicativity comes from them being part of a duality, specifically the organism-environment system

Turvey reviews the fact that this ontology is supposed to be about all forms of life, not simply humans, by noting even cells in bodies can act intentionally in this prospective manner, and single celled organisms (his favourite, Difflugia) can express complex adaptive behaviour reflecting the affordances of it's environment without a nervous system. 

He also revisits the idea of affordances as intensional (with an s, distinct from intentional with a t). Intensions are things like 'can be climbed', and an extension of this intension might be 'a ladder'. Intensions must, in the Establishment view, be inferred from interacting with extensions; they are concepts to be formed. But concept learning faces insurmountable problems (Lecture 16) and affordances cut through this by being intensional and perceivable. (Turvey talks about this in the section on the marsh periwinkle in Turvey et al, 1981; I reviewed the key parts in Wilson, 2021).

So the ecological approach requires an ontology that can replace the Cartesian one that has repeatedly failed us, and that ontology is affordances. 

A Note

You may know of the larger debate around whether Turvey's ontology of affordances is correct, or whether it needs to be made relational instead (I review the basics in this paper I never managed to get past the reviewers at Ecological Psychology). Turvey does not engage with this particular argument per se, although he makes it very clear that affordances are not relations. So he has not refuted the counter argument, he has just firmly asserted his argument (this is a feature of this book, really). 

I fully endorse his approach (this paper currently under review is my current attempt to specifically implement this approach using task-dynamics as well as things like uncontrolled manifold analysis - thanks to a reviewer's questions, the second version contains a lot of specific work explaining how all this makes affordances). Whether or not we are right remains to be seen, although I will note that Turvey style affordances have been empirically very fruitful, more so than the relational approach, which tends to be use in more qualitative, philosophical pieces as a way to describe what might be happening. 

Regardless; for the purposes of engaging with this book, Turvey has made it clear what he thinks affordances are, and we'll be working within that framework for the rest of the book.