John Michael University of Vienna Initiativkolleg: Die Naturwissenschaften im historischen Kontext john.michael@univie.ac.at November 2007 Simulation as an epistemic tool between theory and practice: A Comparison of the Relationship between Theory and Simulation in Science and in Folk Psychology 0. Introduction In this paper, I give reasons for the emergence of a consensus that the two competing accounts of folk psychology – namely, simulation theory and theorytheory – must be combined in order to develop a satisfactory theory of everyday psychological competence. After giving a bit of background on and criticism of simulation theory and theory-theory in the first section, I go on in the second section to pursue the analogy to science that the names of both theories invite. Specifically, I defend the thesis that the analogy to simulations in science shows us how theoretical elements in folk psychology can be complemented by (i.e. not replaced by) the central idea of simulation theory – namely that our own cognitive habits and dispositions provide us with a resource that is distinct from propositional knowledge in folk psychology. That is a descriptive point of psychology. In section three, I inquire whether the analogy to simulations in science can help us to appreciate the relevance of the folk psychology debate for epistemological and ontological questions about mental states. I argue that our use of simulations during cognitive development enables us to imitate the people around us and thereby to become more similar to them, which in turn makes simulation an increasingly effective epistemic strategy. Insofar as theoretical elements – such as the distinctions, relations, and entities referred to in folk psychological discourse – play a role in imitative learning, they are causally embedded in our cognitive development, so we have good reason to regard them as being among the real causes of our behavior. I. The context of the discussion about simulation theory in the philosophy of mind Theory-theory was the more-or-less unchallenged view of folk psychology until the late 1980’s (although it did not come to be called theory-theory until simulation theory arose as an alternative).1 According to theory-theory, which is prominently supported by (among others) Josef Perner, Alison Gopnik and Simon Baron-Cohen, folk psychology is a largely unconscious theory including theoretical entities (mental states such as beliefs and desires) and general psychological laws linking them to each other and to behavior. Since mental states, on this view, are defined by their functional relations, theory-theory is the natural counterpart to functionalism in the philosophy of mind. According to simulation theory, on the other hand, folk psychology is a practice whereby we put ourselves into others’ shoes and simulate their situation from our own perspective. The “radical” version espoused by Robert Gordon denies that either psychological laws or mental concepts are generally employed in folk psychological prediction.2 One of the other main advocates of simulation theory, Alvin Goldman, accepts that mental concepts play a role in simulations, insofar as one must identify one’s own mental state upon completing the simulation procedure before one can ascribe it to another person. But he differs form the theory-theorists in that he claims that there is an introspective component to mental concepts that cannot be captured by their functional roles. Moreover, in deriving a prediction of someone’s action from their input states, 1 The debate has been in full swing since the publication of two volumes in the mid-nineties that collected articles by proponents of both positions: Carruthers, P. & Smith, P., eds., 1996, Theories of Theories of Mind. Cambridge: Cambridge University Press; Davies, M. and Stone T., eds., 1995, Folk Psychology: The Theory of Mind Debate. Oxford: Blackwell Publishers. The introductory chapter of the latter offers an excellent overview and analysis of the initial debate. 2 Gordon, R., 1995, "Simulation Without Introspection or Inference From Me to You," in Mental Simulation: Evaluations and Applications, M. Davies & T. Stone (eds.), Oxford: Blackwell. one employs the same procedures that the target person employs (e.g. practical reasoning), and not separate folk psychological inferential procedures. 3 One problem with simulation theory is that it is simply quite diffuse. Different people mean different things when they talk about simulations. Some propose that in folk psychology we actually imagine ourselves in another person’s situation in order to understand or to predict their behavior. I think it is plausible that we do this sometimes, but we do not seem to do it actively all the time. So what else could simulation mean in this context? Some proponents appeal to motor resonance phenomena, i.e. mirror neurons. There are certain kinds of neural activity that are present when we observe or perform an action. So it seems that perceiving an action may involve some of the same physiological processes as performing an action.4 For simulation theory, this would mean that we correctly anticipate the continuation of someone’s actions simply because we ourselves would continue them in the same way. But this kind of simulation would then always be involved in perception, so there would be no additional process beyond perception that should be called a simulation. Despite this diversity, what is common to simulationists’ accounts is their assertion that our own first-person experiences, habits, and dispositions provide us with a resource other than propositional knowledge that we can use in explaining and predicting others’ behavior. Both simulation theory and theory-theory have other problems to deal with as well. The strongest objection to simulation theory is that simulations cannot work insofar as we are relevantly different from others. So we need to identify the ways in which a target person differs from us in order to set the appropriate parameters. This arguably requires mastery of mental concepts 3 Both of these points are spelled out in Goldman, Alvin, 2006: Simulating Minds: the philosophy, psychology and neuroscience of mindreading, New York: OUP. For the introspectionist account of mental concepts, see chapter 9. 4 Cf. for example: Gallese, V., 2001, "The ‘shared manifold’ hypothesis: from mirror neurons to empathy," Journal of Consciousness Studies, 8, 33-50. Gallese, V., & Goldman, A., 1998, "Mirror neurons and the simulation theory of mind-reading," Trends in Cognitive Sciences, 2, 493-501. defined functionally by their nomological relations among each other and to behavior, since our own beliefs, desires, habits etc. prima facie can’t be of much use to us in figuring out to what extent other people have different beliefs, desires, habits, etc. So we are left with no alternative to inferring their beliefs and desires from their behavior and from what we know about their perceptions. I don’t want to rule out the possibility that there are ways of dealing with this problem within a simulationist account5, but most people agree at least that it presents a problem. On the other hand, there are some fairly persuasive arguments to the effect that theory-theory cannot work without incorporating elements of simulation theory, i.e. our own habits and dispositions. I will mention three briefly: 1. Belief formation on the basis of perception: It seems reasonable that in figuring out what beliefs other people form about a situation on the basis of perceptions, we have to incorporate our own perceptions. I can’t imagine how we could get around using this kind of use of simulation. 2. The Frame Problem: There is a lot of sensory information and also a complex web of beliefs and desires. How do we pick out the ones that are relevant in a specific case? Our own intuitions are a better guide than any formal technique as yet worked out by AI.6 3. Rationality: It is argued by some simulation theorists (in particular Jane Heal7) that a formal theory of rationality could not replace our own intuitions about what is rational. This can be significant for folk psychology in numerous ways. One point is that a theory could not capture the normativity that is inherent in our conception of rationality. We do not always know what follows from our beliefs; we sometimes have inconsistent beliefs; we have to make an 5 Gordon thinks it can be dealt with better within a simulationist account than a theory-theory account, Cf. Gordon, Robert, "Folk Psychology as Mental Simulation”, The Stanford Encyclopedia of Philosophy (Winter 2003 Edition), Edward N. Zalta (ed.), URL = <http://plato.stanford.edu/archives/win2003/entries/davidson/> 6 This argument is worked out by Jane Heal in “Simulation, Theory and Content”, in: P. Carruthers & P.K. Smith, 1996: Theories of Theories of Mind, Cambridge: CUP, p. 75-89 7 This one, too. effort to be consistent and are sometimes corrected, we exchange reasons to defend our inferences. Our judgments of rationality are therefore underdetermined by any formal account. So, insofar as we expect others to behave rationally, we have to rely on our own intuitions about what is rational. A second point is that the prediction of rational behavior in any given case concerns not just principles of rationality, but the application or interpretation of these principles in novel cases. So what we would need is a theory that explains people’s interpretation of the theory of rationality; and this theory would in turn have to be interpreted as well, etc. To avoid the regress, we have to use our own intuition about what is rational. A weaker form of the same argument would be that we always have novel constellations of beliefs and desires, so if we are to use principles to decide what follows from them the danger is that we need new principles for every novel case, and such principles are no principles at all. The upshot is that it is unclear whether either simulation theory or theorytheory can really stand on its own. Indeed, this conclusion reflects the consensus that has emerged. So, given that the two accounts have to be combined, my next question is whether a look at the way in which theory is combined with techniques, practices, experiment, traditions, etc. in constructing simulations in science can help us to figure out how other resources, including mental concepts and psychological generalizations, are combined with something akin to simulation in folk psychology. II. Of what use is the concept of simulation in the empirical-psychological study of folk psychology? First, a couple of general observations. In any kind of simulation in science, theory is required in various ways, but still the simulation can tell us more than the theory alone. So, if theoretical elements have to be added to simulation theory to make it work, this does not imply a collapse of simulation theory into theory-theory. And conversely, the analogy to science should teach us that it should be no surprise that theory-theory in folk psychology needs to be enriched by something beyond theory, such as models or simulations. Given that simulations in science involve/ presuppose some theoretical elements, a natural question to frame the discussion is: when does simulation go beyond theory? In addressing this question, I will draw upon Eric Winsberg’s 8 discussion of the ways in which simulations are more like experimental practice than theory. He makes two main points: 1) We employ a variety of techniques to derive inferences from them (e.g. data analysis, looking at results across a broad range of parameters, visualization) 2) Our judgment of the reliability of simulations depends upon our successful application of them and our successive improvement of them within practical contexts. In this connection, Winsberg refers to Hacking’s dictum: “Experiments have a life of their own”.9 The link to Hacking suggests four characteristics of the relationship between simulation and theory in science that I think can be fruitfully applied to the folk psychology discussion. 1. The construction and use of a simulation can involve numerous theories (in modeling the target system, in building the instruments). In folk psychology, much goes into making us similar enough to others to be used as models of them. For starters, evolution replaces much background theory. But this is not the whole story: In development we learn knowledge about the world, different people’s roles, typical narratives, and also psychological concepts like belief and desire. All of these elements go into making our habits and dispositions similar to the people around us, but: they do not constitute a single theory. Winsberg, Eric, 2003: “Simulated Experiments: Methodology for a virtual world”, Philosophy of Science, 70, p. 105-125. 9 Hacking, Ian, 1983: Representing and Intervening: introductory topics in the philosophy of science, New York: Free Press. 8 2. Theoretical elements need not be actively invoked by the technician using a simulation. Indeed, she may not even know much about them. In folk psychology, I may use abbreviated syllogisms such as: “Tom is angry at Paul. He is going to hit Paul.” There is no reason to insist that I must unconsciously go through a more complete derivation involving all the trappings of formal logic. I can get away with using the abbreviated form simply because the observations and inductions that justify the inference occurred during my developmental history. In fact, I can even employ true generalizations that I have learned from others without myself ever having made the requisite observations: that is a benefit of cultural evolution. 3. Theoretical insights in science may not immediately yield the local predictions we want, but are used to create models or simulations, which are then tweaked over time with the addition of new knowledge and techniques, including rules of thumb for which there is no theoretical justification (e.g. for simplifying calculations, for setting parameters) until we learn how to use and interpret them in particular contexts, etc. Similarly, in folk psychology we add our increasing knowledge about the world, different people’s roles, typical narratives, and also psychological concepts to our apparatus as we go along. Moreover, we have to learn to apply these elements by combining them with the right simulations. For example, it could be argued that predicting behavior on the basis of a false belief involves a concept of belief plus a simulation. The idea would be that once I have figured out what beliefs someone has, the only (or the usual) way to get from the beliefs (in combination with desires and much else of course) to a prediction of action is to imagine I had those beliefs and see what I would do. 4. Applying simulations helps us to gain theoretical insights which, in turn, help us to improve the simulation system. In folk psychology, one can draw a useful analogy to children’s imitative learning. From a very early age, children imitate novel movements and even actions – often with less than complete understanding of the intention guiding the action.10 In so doing, they learn new actions and become acquainted with new intentions (i.e. goals and strategies for achieving those goals). Around nine months, when they begin showing signs of a more sophisticated understanding of their own agency, their imitative behavior increases dramatically11. This suggests that they are using their own recalled experiences of performing actions as a heuristic basis with which they gain a foothold upon adults’ actions. But the interpretation of this data is still controversial. At any rate, through imitation they learn the habits and dispositions that are typical of the members of their culture, which leads to their being cognitively structured in a way similar to the people around them. The result of this is twofold: they can explain and predict others’ behavior more effectively by simulating them, and their behavior can in turn be explained and predicted simulatively by other members of their culture. III. Of what use is the concept of simulation in the discussion of folk psychology in the philosophy of mind? The analogy to science helps not only in developing a descriptive account that combines theoretical elements with habits and dispositions that are not characterizable as propositional knowledge, but also in bringing out the 10 Meltzoff and Tomasello are the two most prominent researchers in this context: Cf. for example, Meltzoff, Andrew N., 2005, „Imitation and other minds: The “Like Me Hypothesis“, in S. Hurley, N. Chater (Ed.), Perspectives on Imitation: From Neuroscience to Social Science Vol.2, Cambridge, MA: MIT, pp. 55-77; Tomasello, Michael, 1999, The cultural origins of human cognition, Cambridge, Mass.: Harvard University Press. 11 Michael Tomasello speaks of the nine-month revolution in this connection: Tomasello, Michael, 1999, The Cultural Origins of Human Cognition, Cambridge: Harvard University Press. epistemological issues about minds that make this discussion interesting to philosophers. It is rather curious that the analogy to science has really only been exploited by advocates of theory-theory in articulating their position – generally either functionalism or eliminativism, depending upon whether one considers folk psychology to be a good theory. Simulation theorists, on the other hand, have not done so, although the very name of simulation theory suggests the possibility of maintaining the continuity between folk and scientific psychology while introducing resources that are of a more practical nature than the theoretical elements postulated by theory-theorists. I think that this is because a different approach has appeared more tempting, namely to suppose that the shift to simulation as an explanation of folk psychological competence undermines the very discussion of the reducibility of mental state terms (and hence the relationship between folk psychology and scientific psychology), since doing justice to our everyday folk psychological competence on a simulationist account does not require us to take mental states seriously. In simulating others’ decision-making processes, we putatively do not need to think about mental states or psychological laws in which mental states figure. Note: this does not necessarily mean that simulation theory is good news for physicalism; on the contrary, it could suggest some kind of dual aspect theory. This is all fine and good insofar as it means that we can make our folk intuitions about minds compatible with scientific psychology simply by interpreting them in a less robust way. But I think we can take this approach one step further if we pursue the analogy to science after all, and simply expand the parameters of the comparison to include not only theoretical elements but also the various practical resources and the history of practical applications with which theoretical elements are intertwined. Again, Ian Hacking’s treatment of experimental practice within the debate on scientific realism suggests an interesting way to cash out on the analogy between folk psychology and science (now on an epistemological level). Hacking asserts that the history of practical application and refinement of scientific equipment and models (and, I would add, simulations) gives us reason to think that they are linked up with the world in a systematic way that has epistemic import. Analogously, I would argue the following: the distinctions that we make in folk psychological discourse (between propositional attitudes such as believing, wanting, and fearing) guide us during development in imitating others and thereby learning from them and becoming more similar to them. One result, of course, is that we become ever-more reliable simulation systems. But the flipside of this is even more interesting: since in cognitive development we use folk psychological notions (such as goals, strategies, beliefs and desires, and attentional states) to guide our simulations (either in actually imitating others or in trying to understand what they are up to), we become increasingly similar to other people as they appear to us when we employ folk psychology (understood as a combination of theoretical elements and habits/dispositions). So other people will be able to effectively employ the same sort of folk psychological resources upon us. In short, the role of folk psychology in cognitive development ensures that it will be an effective way of predicting and explaining others’ behavior. Thus, there is good reason to believe that the distinctions referred to in folk psychology reflect real structures among the psychological causes of our behavior. Insofar as the way in which we employ mental concepts in giving psychological explanations is intertwined with simulations, (i.e. habits and dispositions) during development, the latter could be an irreplaceable resource for scientific psychology. This means that simulation theory (surprisingly) gives us reason to think that mentalist description is not only compatible with scientific psychology, but is indeed potentially useful as such to scientific psychology. So, if you like Hacking’s entity realism, you should also consider becoming a realist about mental states.