Albert Parker May 3, 2001 Functionalism Two Camps Dualist “Mind is formal and abstract” Substance – two radically different kinds of substances in the universe: material objects and immaterial minds (Descartes) Property - two radically different kinds of properties in the universe: material properties (like weight) and immaterial properties (like pain) Materialist “Mind is the wet and slimy stuff in our heads” Behaviorism – mind reduces behavior or dispositions to behavior Physicalism – mental states are brain states Functionalism – mental states are defined by causal relations Strong AI – minds are programs implemented in computers (Searle MLS, p46-7 and SA 31) How do we observe the mind? Dualist’s Problem: Metaphysical Gap The mind can be observed through introspection. that cannot be observed. It is just the minds of others Materialist’s Problem: Leibniz Gap “It must be confessed, moreover, that perception, and that which depends on it, are inexplicable by mechanical causes, that is, by figures and motions. And supposing that there were a mechanism so constructed as to think, feel and have perception, we might enter into it as into a mill. And this granted, we should find only on visiting it, pieces which push one against another, but never anything by which to explain a perception. This must be sought in the simple substance, and not in the composite or in the machine” (CMB, Cummins 4) Analysis of consciousness bogged down for lack of analytical tools! (Psychology crippled and behaviorism was spawned by taking the mind out of psychology) (6-7) What to do? For the materialist, Functionalism provides a bridge over the Leibniz gap: Mental states are defined in terms of their abstract causal roles within the wider information processing system. A given mental state is characterized in terms of its abstract causal relations to environmental input, to other internal states and to output (Churchland, NP, 351). Example 1: Pump is a functional kind, being implemented by hearts, propellor and case, vibrator and one-way valve, centrifuges, piston and sleeve arrangements (MBC, Cummmins 7). Example 2: Mouse Trap is a functional kind, being implemented by spring traps, cage traps, a sack of grain attached to a trip wire, a cat or specially bred killer rat Example 3: Being in pain is a state carried out characterized by its causal relations to: behavior: wincing and crying out external input: skin being burned other internal states: the desire to make the pain go away and belief of what will bring relief. Functional kinds are specified by their roles and not by the material in which they are instantiated. (Churchland, NP, 351). How does Functionalism Deal with the Leibniz Gap? • Functionalism: mental concepts are revealed through function not in terms of intrinsic features. That is, deal with function, to heck with the form. • Leibniz Gap occurs because function can’t be read from form Hence, Functionalism is a bridge over the Gap. “…trying to understand perception by studying only neurons is like trying to understand bird flight by studying only feathers” (Marr 27) “…once we have explained the causal basis of consciousness in terms of the firing of neurons … in the various cortical layers, it seems we still have a phenomenon left over” (Searle MLS, p55) Whose Idea was this? • Emile Durkheim created the functional orientation by codifing the distinction of structure and function in the social sciences. He published his functional analysis in a number of empirical studies: – The Division of Labor in Society (1893) – The Elementary Forms of Religious Life (1912) Durkheim recognized the potential problems of functionalism that critics like John Searle and Patricia Churchland still espouse today in reaction to neurophilosophical functionalism: To discover the need that a structure functions to meet does not necessarily reveal its cause - the sequence of events that created the structure in the first place. To assume it does puts the cart before the horse. (Turner 17) • J. Dewey The Reflex Arc Concept in Psychology (1896) is the “opening shot” of Functionalism in Psychology (Bergmann 678). • H. Putnam “Minds and Machines” in Dimensions of the Mind (1960) was the first to argue that minds are things that we can conceive solely in terms of input, output, and various functional relations. (Hardcastle 2-3) Some Functionalist Achievements • von Neumann architecture (1943-1957) – Still used in today’s desk-tops, lap-tops, calculators and palm pilots that grace every office and half the homes in America (von Neumann xii) • Barlow’s First Dogma (1972) “A description of that activity of a single nerve cell which is transmitted to and influences other nerve cells and of a nerve cell’s response to such influences from other cells, is a complete enough description for a functional understanding of the nervous system” (Barlow 380) • Theory of the Cellebar Cortex (1969) This “regular cortical structure is interpreted as a simple but powerful memorizing device for learning motor skills” (Marr 14) … something was going wrong “I was myself caught up in this excitement (of the 60’s). Truth, I also believed, was basically neutral, and the central aim of all research was a thorough functional analysis of the structure of the central nervous system … the way seemed clear … but somewhere underneath, something was going wrong … the cerebellar study … suggested that one could hope to understand cortical structure in functional terms … but at the same time … it did not much enlighten one about the motor system - it did not, for example, tell one how to go about programming a mechanical arm” (Marr 14-15) “Functionalism looks nice on paper to those who know nothing about how brains work.” (Freeman 115). “Functionalism … is merely the last gasp of classical psychology.” (Bergmann 678) “The functionalist strategem is a smoke screen for the preservation of error and confusion … It needs to be revealed for the shortsighted and reactionary position it is.” (MBC, Churchland 506-7) “If you are tempted to functionalism, I believe you do not need refutation, you need help.” (Searle, TRM, 9) What’s wrong with Functionalism? • ABSURDITIES CAN BE DEFENDED – for example, alchemy, in the face of elemental chemistry, can be defended using the functionalist stratagem, thusly: “Ensouled in mercury” or “sulphur” is an abstract functional state. “Mercury,” for example, actually refers to the disposition to reflect light,to liquefy under heat, to unite with other matter, etc. (these are functional kinds). It is the total syndrome of occurent and causal properties of a metal or substance that matters, not the corpuscularian details of the substrate (function matters, not the implementation). Alchemy, it is concluded, comprehends a level of organization in reality that is distinct from, and irreducible to, the organization found at the level of corpuscularian chemistry. (MBC Churchland 507). • NEED DETAILS! - the success of implementing Neural Networks illustrates that an elementary understanding of brain microstructure funds a fertile conception of what cognition really is. (MBC Churchland 198) • QUALIA can not be reduced to something else, because if you could they would be something else, and they are not something else. (Searle, RM 51) Let’s Patch This Up! “Oceans of Ink have been spilled in the debate over functionalism …” (Hasker 29) • Valerie Hardcastle: “Functionalism is neither very strong nor very controversial.” • Jaegwon Kim: global reductionism is not possible, but some local reductions are: “qualia are intrinsic properties if anything is, and to functionalize them is to eliminate them as intrinsic properties.” (Hardcastle 29). • Elliot Sober: “Functionalism got off on the wrong foot. The problem is that function is ambiguous … ” (97) New Paradigm or Paradigm Shift? • John Searle: “Most of the recently fashioned materialist concepts of the mind – such as behaviorism, functionalism and physicalism – end up denying that there are any such things as minds as we ordinarily think of them … Now, why do they do that? (MBS 15). (We need to stop using) the antique and obsolete vocabulary of “mental” and “physical”, “mind” and “body” (MLS 47). Any satisfactory account of the mind must take into account: consciousness, intentionality, subjectivity, and mental causation” (MBS 17). Reactions: “Many of them, especially the younger generation, agree with me, but I am amazed at the number and vehemence of the defenders” (SA 29) • David Marr: “Almost never can a complex system of any kind be understood as a simple extrapolation from the properties of the individual components … (there are three) levels at which an information processing device must be understood (24-5): Computational Theory Representation and algorithm What is goal of computation and logic of the strategy? What is representation of the input and output and the algorithm map? Hardware Implementation How are the representation and the algorithm realized physically? My Take • Cummins states that if a theory is any good, it must be explanative in and of itself. Some functionalist defenses to attacks sound like the non-intuitive “hook-hook” argument illustrated on page 3 of MBC handout. • Functionalism has problems in its pure form (everything is function, defined in terms of inputs and outputs). NOTE: The new paradigms presented here (at least Marr’s) have functionalist components. • Searle’s paradigm may be a new one. Marr’s is a shift. References • • • • • • • • • • • • • • • H. B. Barlow. “Single snits and sensation: a neural doctrine for perceptual psycology?” Perception 1. G. Bergmann. “The Contribution of John B. Watson.” J. M. Scher editor. Theories of the Mind. The Free Press. New York, 1962. P. S. Churchland. Neurophilosophy. The MIT Press. Cambridge, 1986. R. Cummins and D. D. Cummins. Minds Brains and Computers: The Foundations of Cognitive Science. Blackwell Publishers. Malden, MA, 2000. W. J. Freeman and C. A. Skarda. “Mind/Brain Science: Neuroscience on Philosophy of Mind.” E. Lepore and R. V. Gulick editors. John Searle and His Critics. Basil Blackwell. Cambridge, 1991. V. Hardcastle. How to Build a Theory in Cognitive Science. State University of New York Press. New York, 1996. W. Hasker. The Emergent Self. Cornell University Press. Ithaca, 1999. D. Marr. Vision. W.H. Freeman and Company. New York, 1982. J. von Neumann. The Computer and the Brain. Yale University Press. New Haven, 2000. J. Searle. “Is the Brain’s Mind a Computer Program?”. Scientific American. Jan 1990, p 118. J. Searle. Minds, Brains and Science. Harvard University Press. Cambridge, 1984. J. Searle. Mind, Language, and Society. Basic Books. New York, 1998. J. Searle. Rediscovery of the Mind.. The MIT Press. Cambridge, 1992. E. Sober. “Putting the Function Back into Functionalism.” W. G. Lycan editor. Mind and Cognition. Basil Blackwell. Cambridge, 1990. J. H. Turner and A. Maryanski. Functionalism. The Benjamin/Cummings Publishing Company. Menlo Park, CA, 1979.