Excerpt: This short paper is intended to suggest why computer scientists might be interested in the work of Heidegger, Wittgenstein and others, and to stimulate some further thought about some of the questions that they address. Although Heidegger did not write very much that is explicitly about formal logic, what he did write is quite pertinent, and much of his other work is relevant to questions of meaning in the larger sense. Wittgenstein was concerned with the limits of language, that is, with “what cannot be said.” We will see that their views are fundamentally opposed to those of logical positivists such as Carnap, as well as to the whole Anglo-American tradition of analytic philosophy, and in particular, to Russell and Moore. We will also see some interesting parallels to Buddhist philosophy. At the end of the paper we return to consider what all this has to do with computing.

Key words: Truth, meaning, formalism, Heidegger, Carnap, Wittgenstein, Nothing, computing

This paper presents a framework within which a number of preferred system descriptions can be unified. Of particular interest are the differences stemming from the study of natural systems (biological and social) and man-made systems (engineering and computer). It is claimed that the insights from She study of natural systems have been developed less extensively and precisely. One important case discussed here is the relationship between describing a system as autonomous or as controlled. A precise characterization of complementarity in descriptions is proposed through the notion of adjoint functor, to explicate the interplay of these dual views. Other descriptive dualities of similar kind are discussed, the complementarity between nets and trees is presented in full detail.