In this paper I discuss logic from a naturalist point of view, characterizing it as those shared patterns of thought which are socially selected from among the various patterns of thought to which we are naturally inclined. Drawing on Evans-Pritchard's anthropology. I discuss a particular example of Zande thought. I argue that Evans-Pritchard's and Timm Triplett's analyses of this example make the mistake of applying Western logic to Zande beliefs and thus find a contradiction. I argue that from the naturalistic (...) point of view. Zande logic is different from Western logic and that there is no contradiction in Zande thought. (shrink)

On several occasions I have pointed out that the lesson taught us by recent developments in physics regarding the necessity of a constant extension of the frame of concepts appropriate for the classification of new experiences leads us to a general epistemological attitude which might help us to avoid apparent conceptual difficulties in other fields of science as well. Since, however, the opinion has been expressed from various sides that this attitude would appear to involve a mysticism incompatible with the (...) true spirit of science, I am very glad to use the present opportunity of addressing this assembly of scientists working in quite different fields but united in their striving to find a common ground for our knowledge, to come back to this question, and above all to try to clear up the misunderstandings which have arisen. (shrink)

Paraconsistent quantum logics are weak forms of quantum logic, where the noncontradiction and the excluded-middle laws are violated. These logics find interesting applications in the operational approach to quantum mechanics. In this paper, we present an axiomatization, a Kripke-style, and an algebraic semantical characterization for two forms of paraconsistent quantum logic. Further developments are contained in Giuntini and Greuling's paper in this issue.