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Serious introspection


To do the tasks we will give them, a robot will need many forms of self-consciousness, i.e. ability to observe its own mental state. When we say that something is observable, we mean that a suitable action by the robot causes a sentence and possibly other data structures giving the result of the observation to appear in the robot's consciousness.

This section uses two formalisms described in previous papers.

The first is the notion of a context as a first class object introduced in [McCarthy, 1987] and developed in [McCarthy, 1993] and [McCarthy and Buvac, 1998]. As first class objects, contexts can be the values of variables and arguments and values of functions. The most important expression is Ist(c,p), which asserts that the proposition p is true in the context c. Propositions true in subcontexts need not be true in outer contexts. The language of a subcontext can also be an abbreviated version of the language of an outer context, because the subcontext can involve some assumptions not true in outer contexts. A reasoning system can enter a subcontext and reason with the assumptions and in the language of the subcontext. If we have Ist(c,p) in an outer context c0, we can write


and reason directly with the sentence p. Much human reasoning, maybe all, is done in subcontexts, and robots will have to do the same. There is no most general context. The outermost context used so far can always be transcended to a yet outer context. A sentence Ist(c,p) represents a kind of introspection all by itself.

The second important formalism is that of a proposition or individual concept as a first class object distinct from the truth value of the proposition or the value of the individual concept. This allows propositions and individual concepts to be discussed formally in logical language rather than just informally in natural language. One motivating example from [McCarthy, 1979b] is given by the sentences


Making the distinction between concepts and their denotation allows us to say that Pat knows Mike's telephone number but doesn't know Mary's telephone number even though Mary's telephone number is the same as Mike's telephone number. [McCarthy, 1979b] uses capitalized words for concepts and lower case for objects. This is contrary to the convention in the rest of this paper that capitalizes constants and uses lower case for variables.

We will give tentative formulas for some of the results of observations. In this we take advantage of the ideas of [McCarthy, 1993] and [McCarthy and Buvac, 1998] and give a context for each formula. This makes the formulas shorter. What Here, Now and I mean is determined in an outer context.

The above are only some of the needed forms of self-consciousness. Research is needed to determine their properties and to find additional useful forms of self-consciousness.

next up previous contents
Next: Understanding and Awareness Up: What Consciousness does a Previous: Easy introspection

John McCarthy
Mon Jul 15 13:06:22 PDT 2002