Two notions from philosophical logic and linguistics are brought together and applied to the psychological study of defeasible conditional reasoning. The distinction between disabling conditions and alternative causes is shown to be a special case of Pollock's (1987) distinction between ‘rebutting' and ‘undercutting' defeaters. ‘Inferential' conditionals are shown to come in two types, one that is sensitive to rebutters, the other to undercutters. It is thus predicted and demonstrated in two experiments that the type of inferential conditional used as the (...) major premise of conditional arguments can reverse the heretofore classic, distinctive effects of defeaters. (shrink)

The first main result isolates some conditions which fail for the class of graphs and hold for the class of Abelian p-groups, the class of Abelian torsion groups, and the special class of "rank-homogeneous" trees. We consider these conditions as a possible definition of what it means for a class of structures to have "Ulm type". The result says that there can be no Turing computable embedding of a class not of Ulm type into one of Ulm type. We apply (...) this result to show that there is no Turing computable embedding of the class of graphs into the class of "rank-homogeneous" trees. The second main result says that there is a Turing computable embedding of the class of rank-homogeneous trees into the class of torsion-free Abelian groups. The third main result says that there is a "rank-preserving" Turing computable embedding of the class of rank-homogeneous trees into the class of Boolean algebras. Using this result, we show that there is a computable Boolean algebra of Scott rank ${\mathrm{\omega }}_{1}^{\mathrm{C}\mathrm{K}}$. (shrink)

PAPERS IN LOGIC AND ETHICS by A. N. Prior. Duckworth, 1976. 233 pp. £8.95.THE DOCTRINE OF PROPOSITIONS AND TERMS by A. N. Prior. Duckworth, 1976. 143 pp. £5.95.

This collection of essays delineates the history of the rather disparate intellectual tradition usually labeled as "Platonic" or "Neoplatonic". In chronological order, the book covers the most eminent philosophic schools of thought within that tradition. The most important terms of the Platonic tradition are studied together with a discussion of their semantic implications, the philosophical and theological claims associated with the terms, the sources that furnish the terms, and the intellectual traditions aligned with or opposed to them. The contributors thereby (...) provide a vivid intellectual map of the Middle Ages and the Early Modern period. Contributions are written in English or German. (shrink)

Why is there a 'hard problem' of consciousness? Why do we seem unable to grasp intuitively that physical brain processes can be identical to experiences? Here I comment on the 'meta-problem' (Chalmers, 2018), based on previous ideas (Storm, 2014; 2018). In short: humans may be 'inborn dualists' ('neuroscepticism'), because evolution gave us two (types of) brain systems (or functional modes): one (Sp) for understanding relatively simple physical phenomena, and another (Sm) specialized for mental phenomena. Because Sp cannot deal with the (...) immense complexity of the brain processes underlying consciousness, it represents them as fundamentally different from nonmental physical phenomena (dualist intuition), using 'simulations' to produce 'Sm-type understanding'/predictions that seems radically different from 'Sp-type understanding'. (By analogy, different sensory modalities, handled by distinct brain systems, evoke qualitatively different experiences.) Brain systems for Sp representations of our brain processes never evolved, because they would be useless. When lacking a single 'template' matching different aspects of reality (objective vs. subjective = simulated), complementary 'models' are needed ('neuro-complementarity'), like the wave–particle duality in quantum mechanics. Thus, it seems plausible that Sp and Sm evolved because they were needed to cope with different challenges, and that 'problem intuitions' are side effects of these useful but different brain systems. (shrink)

The posterior parietal cortex (PPC) is the most likely site where egocentric spatial relationships are represented in the brain. PPC cells receive visual, auditory, somaesthetic, and vestibular sensory inputs; oculomotor, head, limb, and body motor signals; and strong motivational projections from the limbic system. Their discharge increases not only when an animal moves towards a sensory target, but also when it directs its attention to it. PPC lesions have the opposite effect: sensory inattention and neglect. The PPC does not seem (...) to contain a “map” of the location of objects in space but a distributed neural network for transforming one set of sensory vectors into other sensory reference frames or into various motor coordinate systems. Which set of transformation rules is used probably depends on attention, which selectively enhances the synapses needed for making a particular sensory comparison or aiming a particular movement. (shrink)

In a discussion-note in Mind, Father P. M. Farrell, O.P., gave an account, in what he admitted to be an embarrassingly brief compass, of the Thomist doctrine concerning evil. There is one sentence in this discussion which at first glance appears paradoxical. Father Farrell has been arguing that a universe containing ‘corruptible good’ as well as incorruptible is better than one containing ‘incorruptible good’ only. He continues: ‘If, however, they are to manifest this corruptible good, they must be corruptible and (...) they must sometimes corrupt.’ The final words, despite Father Farrell's italics, strike one as expressing, not a self-evident truth, but a non sequitur. The fact that I am capable of committing murder does not entail that I will at some time commit it. It is not immediately obvious that a similar entailment holds in the case of corruption and corruptibility. (shrink)