This is most definitely a work under progress. These thoughts came from criticising Anthony Chemero’s “Radical Embodied Cognitive Science, ch. 7 “Affordances etc.” and concludes with the (in)famously ambiguous quote from Gibson on what affordances are defined as.
If affordances are defined as the relation between (or, the relation between is a part of the definition). Then an object need not exist if an agent is not perceiving it. It can, but it needn’t. This will incorporate idealism in full or in part and this is unsatisfactory.
If affordances are defined as the individual ability of an agent and the property of an object, then neither are necessarily coupled. Also unsatisfactory.
However, if abilities and properties are given a compatibility value (a, metaphorical, mathematical/numerical range), which, if in perception of each other are [also] within each others’ range and can thus be combined/actualised/realised. Then, if this is what we wish to call an affordance, is inherent individually in the object and the agent (and thus exist without the presence of each other) but can only be actualised in presence of each other (or by other agents/objects within the same range). Thus, an affordance is neither solely subjective, nor objective, at the same point in time. Or both, if you will. (I hope I got at least a chuckle from this rephrasing of Gibson.)
This view is compatible with evolutionary aspects, ecological aspects but is not selectionist [things Chemero makes a good point of what we should want]. In short and simple, there are many, albeit finite, number of affordances and those that have been directly linked to survival and reproduction (which are temporally and situationally dependent, although this specific aspect falls under biology to explore/have explored) have thus determined our phylogenetic development.
I suggest following terminology (although I have to admit that I am slightly confused by all the existing definitions and so reserve myself for the mistake of reifying someone else’s definition. Should this be the case, I apologize and will credit you accordingly)
Actualised: object/agent in a physically coupled, mutual, dynamic relationship that is temporally bound. (Temporally bound refers to that actualizations of affordances do not last forever, in the most extreme case, we die, but, the temporal aspect is necessary, for development, evolution and dynamicism more generally. Although it can be argued that someone else can keep actualizing what I did before death, this is still another instance, another coupling, that can be simultaneous to my coupling. This thus also holds for collective behaviour.)
Realised: object/agent in a perceptually coupled, mutual, dynamic relationship. (Perceptually bound, spatially bound, geographically bound. Referring to the necessary perception of the object and its affordances and (but not necessarily) the agents affordances and the compatibility range of both. Basically, we need direct perception, and perception at all to be able to realise that there are objects at all etc..)
Both these terms are necessarily physically bound, both by their individual physical properties (body of the agent and shape, density etc. of the object) and the physical constraints of the environment (gravity, exemplifying a more so global constraint, and situationally specific things for example social norms, etc.).
This, allows us realisations in absence of the relevant object but actualizations only in presence. It also allows us to avoid Evil Philosopher arguments, examples of cases when we don’t actualise although we can and failing an attempted actualization.
Arriving at the terribly mundane conclusion that we can interact with things when they are there and they are retained when we are not. To be continued… …probably in my master thesis…