Mind and Theories: Notes on chapter 1 of "Unified theories of Cognition", Allen Newell, 1990
What is a theory? (p13) "Let there be some body of explicit knowledge, from which answers can be obtained to questions by enquiries. Some answers might be predictions, some might be explanations, some might be prescriptions of control. If this body of knowledge yields answers to those questions for you, you can call it a theory." "There is little sense in worrying that one body of knowledge is 'just a collection of facts' (such as a database of peoples heights and ages) and another is 'the fundamental axioms of a subject matter' (such as Newton's three laws plus supporting explication). The difference is important, but it is clear that they answer different sorts of questions, have different scope, and have different potential for further development: i.e. different bodies of knowledge."
Theories are to be nurtured and changed and built up. One aught to be happy to change them in order to make them more useful: almost nay body of knowledge can enter into a theory if it works. An especially powerful form of theory is one which describes a body of underlying mechanisms, whose interactions and compositions provide the answers to all the questions we have.
The word 'cognition' emerged in part to indicate the central processes that were ignored by peripheral perception and motor behaviour. Yet one problem with cognitive psychology has been its persistance in thinking about cognition without bringing in perceptual and motor processes.
Language should be approached with caution and circumspection. A unified theory of cognition must deal with it, but I [Newell] will take it as something to be approached later rather than sooner. [This being a view I personally agree with - perception and movement evolved before language, so I take that to be an indication what I will call, perhaps unjustly, more fundamental processes, and thus of more interest - to me anyway :-)]. We cannot face the entire list [...of human cognitive capabilities...] all at once, so let us consider it to be a priority list, and work our way down from the top. What I mean by a unified theory of cognition is a cognitive theory that gets significantly further down the list than we have ever done before.
According to Newell, the constraints that shaped the human mind are (in the order he listed them): (1) Behave flexibly as a function of the environment; (2) Exhibit adaptive (rational, goal oriented) behaviour; (3) Operate in real time; (4) Operate in a rich, complex, detailed environment, capable of perceiving an immense amount of changing detail, using vast amounts of knowledge, and controlling a motor system of many degrees of freedom; (5) Use symbols and abstractions (known from introspection); (6) Use language, both natural and artificial; (7) Learn from the environment and from experience; (8) Acquire capabilities through development; (9) Operate autonomously, but within a social community; (10) Be self-aware and have a sense of self (meta-cognition?); (11) Be realiseable as a neural system; (12) Be constructable by an embryological growth process; (13) Arise through evolution.
Concerning point 5, I believe that one must be very careful when using introspection when determining constraints of the human mind. For example, introspection tells us that thouhgts occur serially, however, it is well known that the brain is a massively parallel system. This seemingly fundamental difference is explainable by theories of consciousness (e.g. Baars's Global Workspace Theory), but serves as an example of why introspection should be used with caution.
Continuing with the notes... There is a production system called Grapes (Sauers and Farrell, 1982) that embodies the basic production action and automatic creation mechanisms. Finally, there is a book on "Induction" (Holland, Holyoak, Nisbett and Thagard, 1987), is an interdisciplinary effort using different system vehicles: Hollands Classifier Systems and the more classical problem solving systems.