Is there a substantive disagreement here?
Reply to Chemero & Cordeiro*

by Susan L. Hurley

Department of Philosophy
University of Warwick (UK)

I begin with Chemero and Cordeiroís claim that I have misunderstood dynamical systems theory, in two respects. First, I use the concepts of input and output in describing subpersonal relations. Second, I use the concept of causation. Both, they claim, are foreign to dynamic systems theory. Therefore, I get no support from dynamical systems theory in describing subpersons as I understand them as dynamic singularities.

It is hard to locate the substantive, as opposed to verbal disagreement here, and I suspect there may be very little. Our sympathies are obviously very close. At the very end of their commentary they express overall agreement with my main points and say that generally I reject the Input-Output Picture for the right reasons. They come closest to substantive disagreement in saying, at the end of their section A, that though they agree with my conclusion, my arguments against the Input-Output Picture are superfluous. They rehearse many of the points I emphasize, such as the way in which dynamic singularities include more than just the organism. But they donít like the language I use in arguing for these views, since it does not already incorporate the dynamical reconceptualization.

However, for my purposes it would not work to parachute into the conceptualization of dynamical systems theory. Rather, I try to build a bridge to the substance of it from more conventional views about the mind. In particular, I argue against the Input-Output Picture in ways that donít presuppose the dynamical conceptualization. Therefore, I start with the commonplace philosophical conception of the subpersonal as the merely causal level of description, of mechanisms and functions, as opposed to the normative or personal level of description. And I start with the commonplace conception of perception as input to brains, central nervous systems, and/or organisms, and action as output therefrom (see for example, Devitt 1990).

From that starting place, I try to persuade someone to abandon the Input-Output Picture as a conceptual framework. My arguments are addressed to people in that place. I want to show that this picture is unsatisfactory, even if we grant its starting point. Having climbed the ladder, we can go on to kick it away: though the generic concepts of input and output I use are commonplace in neuroscience (see, for example, their use in Deacon 1997), it turns out we donít need these concepts of input and output to capture the relevant subpersonal structure, after all. Thus, I start with input to organisms or central nervous systems or brains (it varies depending on the precise context of argument) and show why perception cannot be captured in terms of such input. The result does indeed bring into question the very idea of input, by blurring relevant boundaries for explanatory purposes, as we agree. And I agree that the idea of a dynamical singularity does not need, in its own terms, inputs and outputs relative to certain boundaries. But it helps to convey this rather alien conception to those who are still immersed in the Input-Output Picture to argue for and express the idea of a dynamical singularity in the first instance in the very terms that it makes unnecessary, in terms of inputs and outputs and feedback relative to the very boundaries whose explanatory value is brought into question (as in my Figure 8.17).

My book is doing exactly that Ďfirst instanceí, bridge-building work, while they are urging me to get on with kicking the ladder away. But nothing in what Chemero and Cordeiro say persuade me that this bridge-building work is philosophically superfluous, given the still pervasive influence of the conceptual framework I am trying to dislodge. Of course there are other kinds of argument for dynamical views, which do not start from here: empirical arguments. But empirical arguments do not make philosophical arguments for conceptual transitions superfluous.

Another probably verbal quarrel is over the use of "causal". Here I think we are simply worrying different bones. I characterize the subpersonal level of description as that appropriate to merely causal explanations, the business of science, to contrast it with the personal level of description employed by folk psychology, where considerations of rationality and normativity are distinctively appropriate. (Reasons may be causes, but if so they are a special kind.) I plead a commonplace generic usage, according to which covering law explanations are paradigms of causal explanations, as opposed to rational explanations or interpretations or justifications or some of the other things we get up to. Merely causal explanations predict and explain by subsuming under generalizations that may be lawlike, but, in contrast with reason explanations, are not normative and do not express rationality. Many such regularities, in physics and elsewhere, are expressed mathematically. In this thin noncommittal sense, Newtonian mechanics is a paradigm of causal explanation. Similarly, the Watt governor account provides a causal explanation, in this generic sense; discrete pushes and shoves are not required. Kelso comments that circular causality is typical of all self-organizing systems (1995, pp. 8-9; see also Clark 1997, pp. 107-108). Chemero and Cordeiro emphasize that there is no reference at all to causation in the Watt governor story. But it is not obvious that causal explanations must themselves use the concept of causation.

As indicated, this thin, generic sense of "causal explanation" functions for my purposes to set up a contrast with the different level of description at which normatively constrained interpretations of rational agents are in play. This usage is found in many textbooks of philosophy of psychology and philosophy of social science; it is not eccentric. But it simply blurs over, doesnít take on, the finer-grained issues about different kinds or accounts of explanation that may fall within the generic category of nonrational causal explanation. Chemero and Cordeiro seem to using a much richer or more specific sense of "causal" than I am. Now maybe there are indeed good reasons to draw further distinctions here, and good criticisms of a rich conception of causal explanation; and maybe these points are linked to a dynamical perspective. But that, I say, is another argument. My project doesnít need any such rich sense of "causal", as they point out. So why attribute it? The commonplace thin notion will do what I need, and as far as I can see my use of it is not deeply incompatible with a dynamical perspective, even though it simply doesnít take on these further issues.

I now move on to Chemero and Cordeiroís claim that I misunderstand Gibsonís ecological view in claiming that it views the relations between perception and action as merely instrumental. My primary basis for this is Gibsonís rejection of the view that internal motor signals play a role in perception, which I see as part of his hostility to information processing in general. (Indeed, I do not see Gibsonís view as a view at the subpersonal level, but rather at the personal (or animal) level, so am puzzled by Chemero and Cordeiroís phrase "ecological subperson".) In Gibsonís view, efference-afference relations are not necessary for an organism to make the self-world distinction, since higher-order patterns of stimulus information would normally do the needed work. Movement makes those patterns available, but it could as well be passive movement as movement involving intentional action. This was the sense in which I claimed that intentional action plays an instrumental role for Gibson, as a means to perception.

In this clear if limited sense, Gibson sees action as a means to perception. Chemero and Cordeiro chide that Gibsonís view of the content of perception supports a view of perception and action as constitutively linked: in particular, his view that affordances for action are perceived. Now, I was certainly aware of this aspect of Gibsonís view. And, more generally, I was certainly aware that ecologists have made strong claims for the intimate links between perception and action (I cited some, in my book, essay 10). But the sense in which the perception of affordances may make the relation between perception and action constitutive is, at least at on the surface, very different from the sense I was concerned with.

Affordances for action, that is, general abilities to act, are what is perceived: part of the content of perceptions, on Gibsonís view. There may well be a sense in which this provides a constitutive link between perception and action. But that by itself does not make the relation between them to be noninstrumental, in the sense relevant to my argument. For that, the relation of a perception to a particular movement or attempt at movement needs to be in question, not merely the perception of that it is possible to act in a certain kind of way.

Suppose I perceive some particular affordance for action: I perceive that it is possible for me to act in a certain kind of way. That perception may or may not itself depend on actual movement (in the way that perception of information in the streaming visual array does). Suppose the perception of an affordance (an ability to act) does here depend on some actual action, which makes information about that affordance available. This actual action may be of a quite different kind from the kind of way in which I see it is possible to act. If there is no such dependence, my distinction doesnít arise. If there is, the next question is: would passive movement do just as well as intentional action, as a means of making information about that affordance available? If so, there is an instrumental relation between the content of that perception and that intentional action. If a general claim is made that passive movement will do the job just as well as intentional action, then this instrumental view of relations between perception and action has been generalized. It makes no difference to this sense of instrumental relation between perception and action whether the content of the perception is about affordances for action or not. In other words, perceptions are not constituted by actions for my purposes by being perceptions of abilities to act.

Thus, while I explained Gibsonís view of affordances briefly in my book, I did not dwell on this aspect of his view: as far as I could see it did not bear on my argument, and I have no quarrel with it. Chemero and Cordeiro may reply that the doctrine of affordances supports a different sense in which perception and action are constitutively linked. That may be so, and perhaps it cuts across my sense of perception depending instrumentally on action. But that wouldnít show that the claim I did make misunderstood Gibson.

Moreover, Chemero and Cordeiro seem to misunderstand my discussion of what it is for an intention to be basic, which is unoriginal and borrows substantially from work by Davidson and Hornsby. As I emphasized, intentions are basic or not only under descriptions, not in themselves, just as actions are intentional or not only under descriptions. We speak of people intentionally doing one thing by doing something else: I intentionally turn on a light by flipping a switch by moving a finger, for example. My action is intentional under these descriptions. It is not intentional under other descriptions, even if they are true: I do not intentionally frighten the burglar, even if he is indeed frightened by my turning on the light. Nor do I intentionally fire the neurons that contribute to explaining my fingerís movement.

Basic intentions are where the chain begins of what I intentionally by doing something else. I donít fire my neurons intentionally at all, so I donít move my finger by firing neurons. But I do flip the switch by moving my finger, since I do move my finger intentionally. There can be borderline cases, and biofeedback, as I discussed, can relocate the distinction between descriptions under which my actions are intentional and descriptions under which they are not.

Whether an intention is basic or not is not a matter of whether it is voluntary or reflex-like. Nonbasic intentions are just as voluntary as basic intentions. Voluntariness is not the issue. Moreover, intentions, whether basic or not, may or may not be conscious. Consciousness is not the issue. There is no parcelling out of activities or parts of activities. There are just different ways of describing the organismís activity, as a whole: at the personal level we describe action, perceptions and intentions, both basic and nonbasic, and at the subpersonal level we describe mere causes, mechanisms, functions. Moreover, I can agree that the boundary between the personal level of intentions and the subpersonal is not always sharp, may shift from case to case, and may admit of differences of degree (see my p. 358, 365, and my discussions of biofeedback; see also the final two paragraphs of my reply to Noë, this symposium).

They describe an example in which involuntary eye movements are prevented, generating an illusion, and imply that it follows on my view that basic level intentions do not change in such a case. I donít follow them here. Basic intentions could change even if the entire body was paralyzed, so that neither voluntary nor involuntary movements were possible. Basic intentions and attempts to move need not be successful.

So I fear that in this area also we are somehow talking past one another. This is a pity, since it would further our cause for those of us impressed with the importance of a dynamical perspective on the mind to present a clear and united front. It is probably in part my fault: while my arguments are complex and have no one Ďnaturalí audience, a more skilful writer might have avoided such misunderstandings. But at least, if my diagnoses are correct as far as they go, there is no deep disagreement here.

More positively, I do think that something more might be made of the suggestion that the concept of affordance links perception and action constitutively. My remarks above have been about the sense in which, in Gibsonís view, perception depends instrumentally on action. But in what way does action depend on perception?

In particular, if we focus on perceived affordances for action on basic intentions, such as "reach rightward", then it seems plausible to me that such affordances could well play an role in showing how the contents of basic intentions can depend noninstrumentally on perception, for example, in situations involving reversing goggles (see my discussion in essay. 9). It would take more work to clarify just how the concept of affordance contributes to this demonstration of constitutive dependence. But this seems a promising area in which to make out an interpretation of Gibson as seeing perception and action as constitutively related in a sense related to my concerns, after all. (I am indebted here to suggestions made by Erik Myin.) Such an interpretation would not negate the point I made above, about the specific sense in which he sees perception as depending instrumentally on action. However, it might put that point into a broader context which limits its significance. Moreover, showing just how the contents of basic intentions can depend noninstrumentally on the perception of affordances might also lead into a converse specification of how the perception of affordances depends noninstrumentally on action. Thus, while I donít think that the point I did make misunderstood Gibson, I accept the possibility that I may have neglected a relevant aspect of Gibsonís position, which would put it closer to the view I favor after all. However, I suspect that working these possibilities out rigorously would require the concept of a basic intention.

* Iím grateful to Erik Myin and David Miller for discussion of these issues.


Clark, A. (1997), Being There (Cambridge, Mass.: MIT Press)

Deacon, T. (1997), The Symbolic Species (New York: W. W. Norton & Co.)

Devitt, M. (1990), 'A Narrow Representational Theory of the Mind' in Lycan, ed., Mind and Cognition (Oxford: Blackwell)

Kelso, J. (1995), Dynamic Patterns: The Self-Organization of Brain and Behavior (Cambridge, Mass.: MIT Press)

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