A. DUALISM:

Problem: We humans have some similarities to both animals and physical objects. So:

1. Are people just a particular kind of animal? or not? Or do people have something special? - eg, Reason, Grammar, Plato's Heaven, apriori knowledge, whatever.

2. Is a person just a particular example of a physical object? Most would want to say yes.

Presumably, Descartes would not accept either of these. Other kinds of dualists might reject the second while insisting on the first.

WHY SUPPORT DUALISM?

1. religious conviction or folk belief: soul, mind, chi (Chin or Jap. ki), etc.

2. introspection: `I trust my conscious experience.'

3. subjectivity: only humans have feelings and experiences yet they only have their OWN feelings

4. show-stopping failure: eg, `animals or machines could never (a) understand language, (b) feel pleasure, etc.'

But should you trust your hunches here? And why is any of these a show-stopper given the magnitude of what is at issue and the subtlety of the phenomena that seem to demand a special non-physical account?

WHY REJECT DUALISM?

1. theoretical simplicity. It seems risky to use such subtle data to force such a strange and radical claim as that humans have something so unique that cannot be contacted

2. implies mental (nonphysical) causation. Physical world has no place for effects of nonphysical things.

3. research methodology: given dualism, psychology (or certain aspects of it) appears to be beyond the realm of explanation by ordinary science since we can't count on finding physical consequences of mental events

4. dependence of mental on neural: If mental substance is independent of its neural substrate, how come there is so much interaction with the physical? A great deal is known about how drugs, etc affect mental experience (pain, visual experience, mood, etc) and how mental experiences correlate with specific neural activity (via PETscans, lesion research), etc. What kind of independence could mind have?

CONCLUSION: Dualism can safely be rejected. The mental (or the spiritual) aspects of being human are just a way of talking about certain kinds of physical processes. We cognitive scientists seek to find out how those processes work. But it is important for us each to analyze and interpret our own folk or prescientific or religious beliefs too.

Aside from religious philosophers, there are few in western science who endorse any kind of dualism explicitly. However, many cognitive scientists (eg, Chomsky and `strong AI' supporters) take an approach that emphasizes apriori formal structures (such as logic, universal grammar, etc). This formal mechanism works like Plato's Heaven (that is, it should not be evaluated by how it happens to run in any physical machine). The time scale is serial only and it does not matter very much how many steps are required. If you can do one rule, you could probably do 20. The mental system is quite independent of its physical instantiation - it is `medium independent'. Chomsky even agrees his work is in the tradition of `Cartesian linguistics'. He puts a little piece of Plato's Heaven in every human baby's head! (Or so says Port.)

B. RATIONALISM AND EMPIRICISM

Rationalists interpret Mind as a distinct Mental (or spritual) substance (Descartes) or as formal processing (Chomsky). Both types tend to believe that many specific `units' are innate and support acquisition of reasoning and language.

Empiricists minimize what is innate and emphasize learning as basis for knowledge.

BEHAVIORISM, (1913- 1960s, esp in US and Britain).

Behaviorists rejected the mind as a worthy topic of study and suggested studying `behavior' in `response' to `stimulation' (all technical terms now, of course).

Key Features

1. objectivist methodology: a kind of operationism, S-R mechanism (but debates continued about physical vs. molar or situational definitions of the Stimulus)

2. animal models. People and animals learn the same way, so it makes sense to do research on animals first.

3. peripheralism - sensory and motor interpretations of `mental events' like thoughts, percepts, intentions, words, etc

4. learning of S-R associative laws as basis of knowledge.

Skinner's ``Verbal Behavior.'' Applied to language what had been learned from animal research. Offered accounts of why a person might utter something, but had nothing to contribute to how it was uttered - what its structure is (which is what Chomsky emphasizes).

Skinner's critique of Chomsky. J'accuse... ``You guys STILL want to put various kinds of little ghosts in people's heads.''

CHOMSKY

Although the idea might predate Chomsky at an intuitive level, Chomsky showed how formal systems could play a role much like that of Soul. The two kinds of stuff (or better `explanatory principle's) become for him Formal systems (Competence) and Physical systems (Performance).

The ellipsis problem, `structuralist principles', parts of speech, phrase structure, etc

Specific formal models. Which are relevant to cognition? How are they relevant?: mathematical group, finite state machine, cellular automaton