|Philosophy of Mind
The Simulation Theory and Explanations that
Angela J. Arkway
ABSTRACT: Underlying the current debate between simulation theory and theory theory is the assumption that folk psychological explanations of behavior are causal. Simulationists Martin Davies, Tony Stone, and Jane Heal claim that folk psychological explanations are explanations that make sense of another person by citing the thoughts important to the determination of his behavior on a given occasion. I argue that it is unlikely these explanations will be causal. Davis et al. base their claim on the assumption that a certain isomorphism obtains between the cognitive mechanisms of human beings. Investigation into the nature of the isomorphism required reveals that it is of a sort that is unlikely to obtain. I suggest that in order to maintain their challenge to theory theory, simulationists must either motivate and describe a non-causal simulation-based account of folk psychological explanation or else delineate a causal account that attributes a nonessential, heuristic role to simulation.
Much interest has been raised recently in cognitive science and in the philosophy of mind by a debate that focuses on the nature of the cognitive mechanism that underlies our folk psychological practices. One side in this debate is represented by proponents of the reigning paradigm, the theory theory. Theory theorists say that our ability to give explanations, predictions and interpretations of intentional behavior is subserved by tacit knowledge of an internally-represented theory of commonsense psychology (Fodor 1987). The simulation theory challenges this view on the grounds that there is no evidence to support the suggestion that we have such knowledge and some evidence to suppose that we do not (Gordon 1986: Goldman 1989). It is more likely, say simulationists, that these abilities are simply underpinned by the innate capacity to simulate others.
Simulationists argue that a compelling case can be made against the theory theory. I do not discuss that case here. Instead I address an issue which, although crucial to the outcome of the debate, has not yet been examined. This issue concerns the nature of the commonsense psychological explanations produced by the mechanism whose functioning both theories claim to describe.
Two assumptions bring the issue of explanation to the fore. One of these pertains to the range and the other to the type of event that the theories are adduced to account for. The merits of the theory theory and the simulation theory are usually discussed in relation to the practice of the prediction of intentional behavior. The reasonable assumption, (assumption A), is that the mechanism that is deployed in prediction will be the same one that is deployed in the explanation, the description and the interpretation of our own and others behavior. The second assumption, (assumption B), is that the two theories offer competing accounts of the same sort of event. The theory theory and the simulation theory, in proposing alternative views of the mechanism underlying our folk psychological practices of prediction, explanation, etc., agree on what these practices consist in.
With regard to explanation, the grounds for assumption B are not clear. Theory theorists hold that the commonsense psychological explanations of behavior produced by theory deployment are causal explanations. Those who think that the folk theory is internally represented in the form of psychological laws have a ready-made model of causal explanation available to substantiate this claim, the covering law model. Just like explanations in basic science and in the special sciences, they point out, folk psychological explanations are deductive arguments in which a commonsense psychological covering law is implicitly deployed.
Simulationists are not explicit about the kind of explanations produced by simulation. Nevertheless grounding assumptions A and B requires spelling out the conditions that a correct simulation- produced folk psychological causal explanation of behavior satisfies. Since simulation theory is founded on the premise that there is no body of internally-represented commonsense psychological knowledge, and consequently no laws in which it is represented, appealing to the covering law model of causal explanation is not an option. What simulation needs in order to substantiate assumptions A and B is a causal account of folk psychological explanation whose satisfaction conditions either involve simulation essentially or, if they do not, are at least compatible with simulation as an heuristic device for picking out what is the most likely to be the correct causal explanation. In this paper I discuss a suggestion for explanation which assigns an essential role to simulation.
In the next section, after laying out a general version of the simulation theory, I describe a view that has been proposed recently both as a version of the simulation theory and as a type of theory that stresses the idea of a distinctive kind of explanation. In Section Three this simulation-based proposal for explanation is developed and in Section Four the view is examined with regard to its potential to fill the simulationist need for an account of causal explanation.
II. The Simulation Theory
A theme common to all versions of the simulation theory is that when we predict the behavior of another person, or of ourselves at a time remote from the present, the mechanism which governs the daily interaction of our beliefs, desires and other intentional and qualitative states, the practical-reasoning mechanism, is disengaged from its actual inputs, viz. from external stimuli and from our own salient beliefs and desires. At the same time, this mechanism is disconnected from the action controllers, the mental mechanisms responsible for a decision-to-behave being translated into actual behavior. Operating "off-line" in this manner, the decision-making mechanism is fed pretend-input in the form of those beliefs and desires we imagine we would instantiate ourselves if we were in the situation of the person whose behavior we are about to predict. The practical reasoning mechanism then processes these pretend inputs and a pretend decision-to- behave is generated. This pretend decision-to-behave is transformed into the prediction of behavior. Commonsense psychological explanations of behavior are produced in a similar way, claim simulationists. In explaining a behavioral episode we feed into our disengaged decision- making mechanism those beliefs and desires we imagine are likely to produce a decision to perform the behavior we want to explain.
Martin Davies and Tony Stone (1996, p.136) pointed out recently that there is a type of theory which qualifies as a version of the simulation theory under some construals of simulation, and stresses the idea that commonsense psychological explanations are explanations that "make sense of another person." According to this view, in making a decision to act one "...bring[s] to bear [ones] knowledge about the world, and arrive[s] at a judgement about what is the thing to do." Davies and Stone admit that both knowledge and imagination are drawn upon here, but insist there need be no intrusion into ones own decision taking of any body of empirical theory about psychology about what people in certain situations and with certain propositional attitudes generally tend to do (1996, p.136). The same kind of normative judgment is relevant when we explain or understand the behavior of another person, say Davies and Stone. They agree with John McDowell that
Davies and Stone suggest that this type of theory may count as a variation on the simulation theme according to Stich and Nichols way of drawing the "battle lines." Stich and Nichols (1992, p.47) consider any theory that involves processing in the decision-making mechanism when it is disconnected from its natural inputs and from the action controllers ("off-line" processing) a version of the simulation theory. Since the strategy described by Davies and Stone has the explainer feeding into his own practical decision-making mechanism facts about the circumstances in which a decision-to-behave was made by another and this mechanism generating a pretend decision-to-behave which is not then translated into behavior, it does seem to meet Stich and Nichols rather broad condition for simulation.
III. Explanations that Make Sense of Behavior
Davies and Stone do not address the issue of whether simulation-generated folk psychological explanations that make sense of other people are causal. In this section I suggest an account of folk psychological explanation based on Davies and Stones view of the strategy deployed in explanation-giving and examine it with regard to its potential to fill the simulationist need for an account of causal explanation. The suggestion is the following:
One simulationist who would be quick to point out that there are folk psychological explanations of behavior that do not satisfy these, or any other, simulation-based conditions is Jane Heal. Heal says that "...the only cases that a simulationist should confidently claim are those where (a) the starting point is an item or collection of items with content, (b) the outcome is a further item with content, (c) the latter content is rationally or intelligibly linked to that of the earlier item(s)" (1996b, p.56). Following Heal, let us suppose that the domain of explanations in which simulation is essentially involved is limited in this way and see whether satisfaction of the simulation-based condition at (SE)* is likely to be necessary and/or sufficient for a correct one.
Let us take the case of Philip who decides to take up smoking and smokes his first cigarette while working on his dissertation. Let us suppose that the correct commonsense psychological explanation of Philips smoking is "Philip smoked because he wants to finish writing his dissertation and he believes that he will write more easily while smoking." Philips case clearly qualifies as a candidate for Heals type of simulation in that his belief and his desire are contentful states that are intelligibly linked to each other and to his decision to smoke. The next step is to examine what, in Heals view, would be the case if this correct explanation were to satisfy the simulation condition (c) at (SE)*.
Heal (1996b, pp.59-60) points out that recent thought in moral psychology and in the philosophy of action more generally has developed a view about the conception of desires, emotions and intentions which affects how we should conceive of simulating these states. This conception emphasizes the links between the whole motivational and affective side of our nature and the concept of the valuable: the desire that p, for example, should be understood as being closely linked to conceiving that it would be valuable in some way, enjoyable, health promoting, just, if p. Heal points out that since phenomena like akrasia, depression and overreaction show that the strength of motivation or feeling can get out of line with what is rationally licensed by the associated judgments, the states in question cannot be identified with the value judgments. However, she adds, this does not indicate that there is more to simulating a desire, an emotion or an intention than entertaining the content of the associated value judgment. She points out that "[A]s far as rationalizing and making intelligible are concerned it is the value judgments that do the work" (1996b,p.60).
On this view then, the explanation of Philips smoking will satisfy (c) at (SE)* iff the value judgment attached to his desire to finish his dissertation, i.e. that finishing his dissertation would be a very good thing indeed, is correctly simulated such that this desire emerges from a simulation of Philip, together with the belief that he will write more easily while smoking, as the belief and the desire that make best sense of Philips decision to smoke in the circumstances in which he actually made that decision.
IV. The Question of Isomorphism
Heal suggests that what is responsible for our success in simulating is the remarkable cognitive machinery with which we are endowed. This machinery, besides empowering us to pick out from our own world view the factors relevant to any given problem, also "enables us to pick out from anothers world view the particular thoughts important to determining his or her behavior in a specified case" (1996a, pp.84-5). She adds: "To apply the remarkable machinery to someone elses world view so as to extract from it the thoughts relevant to answering a particular question is precisely to simulate his or her thought." In dealing with others, in particular in predicting their thoughts "we take account of the fact that they have the ability to cope sensibly when other things are not equal or circumstances are not normal" (1996a, p.81).
Heals claim about the role of simulation in our folk psychological practices relies on two assumptions: first, that our cognitive machinery is such that we have the capacity to simulate successfully the rationally-linked contentful states that another instantiates on a specific occasion and, second, that the cognitive machinery responsible for this competence is isomorphic, or relevantly similar, in human beings. It is with the posited isomorphism or relevant similarity that I take issue here. It seems that even if it is true that the cognitive structure in human beings is such that it allows some sort of simulation, it does not follow that the cognitive machinery in question will be strictly isomorphic, or even similar enough to account for the role that Heal attributes to simulation. Below I discuss the question of the sort of similarity necessary in order for one human being to pick out "from anothers world view the particular thoughts important to determining his or her behavior in a specified case" (1996a, p.84).
One possibility is that the similarity consists in the fact that the cognitive mechanism incorporates some sort of norm of what it is for one thought to be rationally connected to another and what it is for a thought to be rationally linked to behavior. However it does not look as though our being similar in this respect will suffice to account for our ability to explain rational behavior. Imagine the ideal case in which a potential explainer, thus equipped, succeeds in simulating all of the relevant contentful states that a similarly-equipped behaver instantiated on the occasion of his decision to behave. What processing according to a norm might extract from the complex of correctly- simulated mental states are those which, among all the ones the behaver actually instantiated on the occasion of his decision to behave, are the most likely to be instantiated by a rational behaver in relation to the kind of behavior in question in circumstances of the type in question. There is no reason to believe that these are what actually caused the behaviorial episode at issue. The posited isomorphism between the cognitive mechanisms is simply too weak to support such a suggestion.
If we construe the similarity in cognitive machinery as strong to the degree that it allows the rationally-linked contentful states causally relevant to a specific behavior on a particular occasion to emerge from a simulation more often than not, the issue about cognitive similarity becomes a question of the degree of similarity necessary to account for our (apparent) success in explaining. I suggest that this degree is likely to be implausibly high. For it seems that in order for these states to emerge from a simulation the explainer must simulate correctly not just the content of the behavers mental states and the rational links between them, but the ranking in the value judgments attached to the behavers desires, emotions and intentions and the hierarchy in the strength of the (relevant) beliefs that obtained at the moment the behaver made his decision to behave.
To return to the case of Philip; if the desire to finish writing his dissertation and the belief that he will write more easily while smoking are to emerge from a simulation of Philip as those that are explanatorily relevant to his decision to smoke, then the simulator will succeed in at least the following tasks. Besides simulating the content of the value judgment attached to Philips desire to finish his dissertation, viz., that finishing it would be a very good thing indeed, he/she will simulate the ranking of this value judgment in relation to the value judgments attached to any other state in the inter-related complex of relevant states that Philip instantiated at the time he made the decision to smoke, viz., that finishing his dissertation ranked higher for Philip in the circumstances in which he made the decision to smoke than, for example, the value judgments attached to his firm intention not to expose his two-year old to the noxious effects of second-hand smoke, to his deep-seated fear of becoming addicted to nicotine and to his standing desire to preserve his chances to live a long and pain-free life. The simulator will also simulate successfully the degree of strength carried by Philips belief about smokings effect on his writing in relation to his other beliefs about writing and about smoking and, if it is true, as Heal (1996a. p.79) says, that "no thought, whatever its subject matter, can be ruled out a priori as certainly irrelevant to a given question," even in relation to indeterminately many of his other beliefs .
So it turns out that Heals suggestion that our cognitive machinery "enables us to pick out from anothers world view the particular thoughts important to determining his or her behavior in a specified case" presupposes a degree of similarity between the cognitive mechanisms of human beings that is likely to be much higher than the degree required to simulate the content and the rational links between anothers beliefs, desires, etc., and associated value judgments. This degree needs to be such that it allows one person to simulate the "weighting" that another attributed to a large section of his/her inter-related complex of mental states on a specific occasion. That the cognitive mechanisms of human beings are similar to a degree that allows this sort of simulation is far from self-evident.
This finding has important ramifications for the simulation-theory theory debate. If, as Davies, Stone, and Heal say, folk psychological explanations are explanations that make sense of behavior and involve simulation essentially, and if the degree of similarity required for the explainer to cite the states causally responible for the behavers behavior is unlikely to obtain, then it is unlikely that folk psychological explanations are causal. In this case the assumption that the simulation theory and the theory theory are accounting for the same type of explanation-giving (assumption B), i.e. causal explanation-giving, will be unfounded. Simulationists will need to say both why they think folk psychological explanations are not causal and to spell out the conditions that a correct simulation-involving non-causal folk psychological explanation that makes sense of behavior satisfies.
A different, and less radical, way to save the suggestion of Davies et al. involves attributing a non-essential role to simulation in explanation. If the role of simulation in explanations that make sense of behavior is to merely pick out from a range of belief-desire sets the one that is the most likely to be the correct causal explanation, then simulation will not be essentially involved in the conditions that the correct causal explanation satisfies. Our remarkable cognitive machinery being such that it allows us pick out the correct explanation often enough to account for our successful interaction does not entail simulation being either necessary or sufficient for a correct explanation that makes sense of behavior. If simulationists take this route they will still owe us a causal account of folk psychological explanation, one that is both compatible with the simulation heuristic and, if they wish to maintain their challenge to the theory theory, does not appeal to an internally- represented tacitly-known theory of folk psychology.
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