Provability, Computability and Reflection.

We introduce the notion of an alphabetic trace of a cut-free intuitionistic prepositional proof and show that it serves to characterize the equality of arrows in cartesian closed categories. We also show that alphabetic traces improve on the notion of the generality of proofs proposed in the literature. The main theorem of the paper yields a new and considerably simpler solution of the coherence problem for cartesian closed categories than those in [11, 14].

In this paper, we approach the problem of the relationship between Greek mathematics and Eleatic philosophy from a new perspective, which leads us to a reappraisal of Szabó’s hypothesis about the origin of mathematics out of Eleatic philosophy. We claim that Parmenidean philosophy, particularly its semantic core, has possibly been shaped by reflexion on the Pythagoreans’ mathematical practice, particularly in arithmetic. Furthermore, Pythagorean arithmetic originates not from another domain outside mathematics but from counting, i.e., it has its roots in man’s (...) practical activity. This interpretation restores the historically inverse relationship between mathematics and philosophy, refuting the attribution of mathematics’ origin to a field outside mathematics, for which Szabó’s hypothesis has been criticised. Moreover, Parmenidean theory of truth is viewed not as a defective predecessor of Aristotle’s classical theory of truth that needs to be remedied but as a semantic conception coordinated with the mathematics of Parmenides’ times. (shrink)

A recent analysis by de Barros and Suppes of experimentally realizable GHZ correlations supports the conclusion that these correlations cannot be explained by introducing local hidden variables. We show, nevertheless, that their analysis does not exclude local hidden variable models in which the inefficiency in the experiment is an effect not only of random errors in the detector equipment, but is also the manifestation of a pre-set, hidden property of the particles ("prism models"). Indeed, we present an explicit prism model (...) for the GHZ scenario; that is, a local hidden variable model entirely compatible with recent GHZ experiments. (shrink)

Professor Meehl [2] has pointed out a very significant problem in the methodology of psychological research, indicating that statistical tests of psychological hypotheses against a null hypothesis are loaded in favor of eventual success at rejecting the null hypothesis. In my opinion this is not, however, a contrast between physics and psychology, but rather between the method of parameter estimation and that of the null hypothesis in the tradition of Fisher. A physicist could use the null hypothesis method as well (...) as the psychologist. The fact that he doesn't is probably related to the more advanced state of his measurement techniques and theoretical constructs. (shrink)

BY OVEREMPHASIZING MATERIALISTIC VALUES, we have perverted the culture and set modern Western civilization on a self-destructive course. Some critics have said that the economy, science, and technology are the only healthy aspects of our society. We have what I have called a saber-toothed tiger civilization. In the evolutionary process, the saber-toothed tiger developed great tusks as effective weapons in combat, but perished because they obstructed its eating. We have developed a culture that is highly successful in advancing science and (...) technology and producing wealth and power, but in doing so we have undermined and subjectivized the sectors of the culture that underwrite our identity, the meaning of our existence, and the norms and values by which we live our lives, organize our society, and run our institutions, including even science and the economy. But unlike the saber-toothed tiger, we can discover our error and correct our course. (shrink)

The Birkhoff-Maltsev problem asks for a characterization of those lattices each of which is isomorphic to the lattice L(K) of all subquasivarieties for some quasivariety K of algebraic systems. The current status of this problem, which is still open, is discussed. Various unsolved questions that are related to the Birkhoff-Maltsev problem are also considered, including ones that stem from the theory of propositional logics.