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. 

Lecture 5: The Mechanistic Hypothesis (Turvey, 2019, Lectures on Perception)

In the previous lecture, Turvey spent a lot of time defending the idea that nonlocal causality is a legitimate option for a physical system. He did this by looking at quantum mechanics and the extraordinarily robust evidence it has provided for nonlocality. The reason he did this is because perception as a two-term relation (direct perception) seems to require at least some nonlocal causality in order to work without additional terms (epistemic mediators). 

This chapter is a discussion of properties and how to organise them - ontology. Part of Turvey's work is to lay bare the fact a lot of our science is still working within the 17th century, mechanistic framework - all psychologists have encountered the idea that there are primary and secondary properties of things, and that we are in the business of understanding how the secondary ones work. But, as Turvey is describing, science has moved on, and the possible types of legitimately physical (primary) properties has expanded far beyond what Galileo, etc thought possible. For example, in quantum mechanics, particles don't have properties such as 'position' or 'velocity' until they are placed into a relation with either a position or a velocity measuring device. The property 'position' is impredicative, both defined and actualised by the presence of the relation to a position measurer. Historically, properties that are both defined and actualised by the property holder is in the relation have been considered to be secondary properties; subjective, not objective properties. But quantum mechanics considers particle position to be perfectly real, and it has the extraordinary level of empirical success required to back that claim up. 

This chapter walks the reader through the development of the mechanistic framework that still drives how we classify properties, thus affecting how we study them. It ends by identifying that this taxonomy begins to creak as we use it at the scale of behaviour, and points to the success of quantum physics to suggest a more expansive and interesting taxonomy of real properties is both required and an option. 

Scarantino (2003) “Affordances Explained”

Turvey, Shaw, Reed and Mace (1981) laid out an ontology of affordances; a formal account of the kind of things they are. They described them as dispositions, properties of the world constituted by sets of anchoring properties that offered an action to an organism whose dispositions could complement the affordance. Making affordances dispositions makes them real, makes them pre-date the interaction with the organism, and accounts for their odd ‘not doing anything until interacted with’ kind of existence. I am firmly Team Affordances are Dispositions and I have yet to meet an alternative account that supports a science of affordances or even allows them to be perceived.

The literature on dispositions was somewhat limited in 1981, but in 1998 Stephan Mumford published the definitive work on what they are and how they work. I always hoped someone with the necessary philosophy chops would use this work to strengthen the foundations of affordances (I even almost talked a philosopher into doing it!) but it turns out I’m covered. Andrea Scarantino (2003) published ‘Affordances Explained’ and did much of the necessary work, and there are some very useful things in the analysis. This post is me working through this material, translating from the technical philosophy into words I can understand better.