TA112 (MŁller)


Commentary 13 (to C12 by Moodey)




by William A. Adams

17 April 2009, posted 25 April 2009




I am an appreciator of Alva NoŽís theory of ďenactive perception,Ē on which Richard Moodey recently commented.I will address some points raised by Moodey.



Moodey objects to NoŽís use of a false dichotomy between perception as activity and perception as representation.Moodey wants to say ďboth.ĒMoodey: ďI also hold that there is also a passive moment to perception.There is a stimulation of receptors by light (chose your theory of light, by sound waves, by airborne chemicals, etc.) These stimuli have their own structured characteristics.Ē



That sounds like a reasonable approach but it does not add anything and thatís why NoŽ treats sensation per se as unimportant.He would not deny that there are energy specific sensory transducers, but that is of no interest. Stimulation from the world becomes neural impulses routed to the brain, but then what?There is no known, or conceivable pathway to get from a neurological pattern in the brain to a personís subjective understanding, or experience.It is an epistemological dead-end.



NoŽ avoids that cul-de-sac by framing perception entirely as a transactional process, much as James Gibson did (The Ecological Approach to Visual Perception, 1979). On this model, every perceptual act is an exploratory gesture satisfied by features of the environment (what NoŽ calls a sensorimotor contingency).Gibson said an animal perceives ďaffordancesĒ of the environment, features that offer physiologically and morphologically appropriate behavior. A hole in a tree affords hiding for a bird but not for a horse.A solid, level terrain is walk-on-able for a person, but the surface of a pond is not perceived as affording locomotion.Affordances are behaviorally relevant features of the environment taken with respect to the animalís capacities. There is no need to invoke neurological representation.




Gibson was a behaviorist, so he hit an impasse trying to explain how the animal appreciated its affordances.He allowed of no mentality, no subjectivity.His wasan analysis of perception nominally free of subjectivity, and as such was ultimately not successful.He resorted to euphemism, saying that the animal directly ďpicked upĒ the affordances or ďresonatedĒ with them. Even in his Thursday afternoon seminars he could not explain what that meant.



Moodey insists on the possibility of passive perception. However, it does not lead inevitably to perceptual experience. Recent studies of change blindness and inattentional blindness demonstrate that. You can be sittingat a red light, looking right at it, the red wavelengths stimulating your retinas and signals flowing to your brain, and still, you might not notice that the light has changed until the car behind you starts honking.By contrasting his enactive approach to the traditional representational approach to perception, NoŽis merely saying that stimulation of sensory receptors is not sufficient for perception.



Nevertheless, NoŽ does not give a strong explanation of what is sufficient to make perception happen. He says, ďThink of a blind person tap-tapping his or her way around a cluttered space, perceiving that space by touch, not all at once, but through time, by skillful probing and movement.This is, or at least ought to be, our paradigm of what perceiving is.Ē (Action in Perception, 2004).But how, exactly, does the blind person construct an understanding of the environment out of tactile sensations? NoŽ doesnít say.He seems to allow in general the existence of subjective phenomenology, but offers no account of attention, intentionality or cognitive synthesis.That is a weakness in his description. Functionalism (which is what he seems to adopt, without naming it), is psychologically hollow.It confines subjectivity and mentality to a black box, and will discuss only the inputs and outputs.Unlike the behaviorist, the functionalist is free to discuss mental concepts like information (in) and understanding (out).Functionalism does not deny subjectivity, because itís in the box, but as a practical matter, since nothing is said about the boxís contents, the box acts as an arbitrary stipulation rather than as an explanation.



When NoŽ says that the world is its own representation, he is saying as Gibson did, that the affordances, or patterns perceived, are in the environment, not in the head.In other words, there are no neurological representations.



I am also anti-representationalist, mainly because of the homunculus problem.If there were neurological representations, who would consult them?And how?And for what reason?Nevertheless, I donít think Gibson or NoŽ has offered an adequate alternative.My own is not ready for the sunlight.




Bill Adams

†††† Email <bill.adams(at)waadams.net>