The strongest modern proponent of their being specification, was Gibson, and he might be the only person in history with a real theory about specification (this started with the 1961 Ecological Optics paper, though the final version has some modifications from there). There were an intense series of debates about this back in the early '80's and a much more recent set of arguments by Withagen and Chemero and others. While I am still unsure about the current debates, I am convinced that the earlier arguments were confused because no one in the debates understood the context of Gibson in the lineage of philosophy that started with Pragmatism - neither ecological psychology's critics or its proponents understood. Gibson certainly knew he was in that lineage, but I am unsure how well he understood his connection to it, and Gibson died a few years before these fireworks started. Turvey, Shaw, and Mace (TSM), the new vanguard, did not have a strong connection to that tradition.
My understanding of Gibson is quite different than TSM, it connects strongly with the work of Charles Sanders Peirce, though my understanding of Gibson developed a decade before I was exposed to Peirce. I have been trying to engage a Peirce scholar in writing about the connection, which I think could clarify many issues in ecological psychology. What comes below is sketch of that project, with an emphasis on how it is relevant to the debate about specification.
Truth-seeking and TruismsWe need to start with a basic principle of truth-seeking and a truism. The first is a principle from Peirce, which I will not try to defend here, but would be happy to write more about later. The second is a truism from William James, though it could have come from others.
Truth-seeking: To have true knowledge of the world it is not crucial that you are never wrong, it is only crucial that you are always wrong in a way that allows you to self-correct.
Truism: All situations are different, and all differences are (in principle) detectable... because a (as William James pointed out) there is no difference that doesn't make a difference.
Building a Theory
Gibson's direct-perception argument is a limited instantiation of Peirce's truth-seeking mechanism. Peirce intended the mechanism as broadly as can be imagined, to cover the discovery of truth of the most basic facts of the world and the most derived ideas. Gibson had a more focused interested in the basic mysteries of perception, as commonly understood - how do I get along in the world that I see, pick up my coffee cup, walk through the room, play a game of catch, etc. For Gibson, acquainted with the long view of historic debates about perception, it would be a major accomplishment to show that direct perception was possible. He argued that the ambient energy in the environment specified the objects and events in the world around us. This was a major conceptual leap, the leap of recognizing the existence of a "stimulus ecology" in which specification must occur... but as much as it was a major leap, it is also just a rephrasing of our truism. The existence of ambient-energy-with-structure-specific-to-the-surrounding-world hadn't really been considered before, because, for historic reasons, philosophers of perception were obsessed with things that they knew were ambiguous (e.g. projective images). A stimulus ecology can be explored, ad infinitum. Once can move around objects, get closer to them, interact with them. If one can engage with this energy in the right way, one can know infallibly about the world around them.
There isn't really any reason to go any further into Gibson-land, in my opinion, if that first part can't be agreed upon. If you don't believe you are surrounded by lights and sounds and floating chemicals throughout your day to day life, go no further. If you believe that two objects could be different in a way that is in principle undetectable, because no means of interacting with the objects will lead them to affect their environment differently, go no further.
If you agree with those points, then we have the fundamentals of an argument for direct perception - we do not have an argument that organisms always perceive the world perfectly, but we have an argument that organisms could perceive the world correctly under the right circumstances, with no intervening mental stuff required. And that is all we mean by "direct". With that agreed upon, our inquiry into perception then shifts to relevant organism-environment processes on very different time-scales: evolutionary tuning, developmental tuning, "in the moment" exploration. These processes are relatively crude, but they have a lot of potential.
- Evolution favors accurate behavior; although it is just as happy for crude shortcuts most of the time, it still favors organisms with the abilities to be sensitive to the types of information that specify the objects and events relevant to their niche/Umwelt.
- Development favors accurate behavior; it is highly dynamic process, and organisms are startlingly good at developing in ways that match the demands of their environment.
- Exploration is where those mechanisms converge in the interaction of organism and environment, where the ambient energy allows for the detection of object and event properties.
If someone is still trying to challenge the direct perception argument, there should only really be two lines of argument remaining open to them:
- "That's all fine and good, but in practice, you will never find an organism attuned to the correct variables."
- "Hey, back up a second, infinite uniqueness isn't really the issue here!"
Back to PeirceMy point here is to say that if people try to fit Gibson's ideas into the framework of continental philosophy, then there are going to be problems, and you are going to end up in places where the ideas cannot be defended. Gibson's work fits into a different framework, one that challenges the starting place of its opponents on such a fundamental level that trying to argue things at the level of Gibson's theory of perception is to start the argument way, way, way ahead of where the actual disagreement lies. Example: In the continental tradition, you only need one illusory phenomenon to show that your opponent can never be 100% sure of anything perception tells him. In the pragmatist tradition, the fact that your argument is premised upon already knowing that the phenomenon-at-issue is illusory clearly indicates the potential for correct knowledge.
In the pragmatist tradition, the crucial factor is to be able to move towards the truth, to adjust one's self toward ever increasing accuracy. Gibson articulated a detailed mechanism that allows organisms to do this, at least within a clearly demarcated set of circumstances: The interaction of organisms with objects and events on an ecological scale of analysis, as mediated by their perceptual systems. Though this is less ambitious than Peirce, the limitation allowed for rapid advancement of the conceptual infrastructure needed to support the argument.
These ideas need to be drawn out more thoroughly, because I think they will help clarify both what ecological psychologists are up to, and why there is such a strong tradition of debates in which people seem to talk past each other. Hopefully this is making sense so far. If there are any Peirce scholars out there who think this sounds interesting, please comment!