Chrysippus claims that some propositions perish. including some true conditionals whose consequent is impossible and antecedent is possible, to which he appeals against Diodorus?s Master Argument. On the standard interpretation. perished propositions lack truth values. and these conditionals are true at the same time as their antecedents arc possible and consequents impossible. But perished propositions are false, and Chrysippus?s conditionals are true when their antecedent and consequent arc possible, and false when their antecedent is possible and consequent impossible. The claim (...) of the Master Argument that Chrysippus rejects, then, is stronger ihan usually supposed. (shrink)

While recent studies have shed some light on the significance of the electrical activity of the nervous system, there has been no adequate explanation for the wave formation or synchronization of this electrical activity. Adrian sums up the problem. “The origin of the 10-a-second rhythm is still uncertain, though the evidence points to some widespread organization, probably involving the central masses as well as the cortex. There are abundant nervous connexions for coordinating the beat, and when the rhythm is well (...) developed it is possible to record impulse discharges in phase with it passing to and fro in the nerve fibers of the white matter below the cortex. But in some areas no impulse could be detected entering or leaving the cell layers, though the potential waves keep more or less in step with those elsewhere. There is no proof that the waves are kept in phase by some means which does not involve nervous signalling, for impulses in axons of small diameter might well be missed, but it is not altogether unlikely that the synchronization is due in part to a direct electrical influence of one group of nerve cells on another. Gerard and Libet have shown that synchronization can occur between the two halves of a frog's brain cut in two and then placed in contact, and more recently Arvanitaki has shown that individual nerve cells may influence one another if they are brought close together in a conducting medium. At all events there are many examples of synchronized rhythmic activity in large collections of nerve-or-muscle cells. In the optic ganglion of the water beetle, for instance, there may be both a slow rhythm when the eye is in darkness and a rapid one when the eye is exposed to a bright light. The change from a slow to a fast rhythm is curiously reminiscent of that in the cerebral cortex when a sensory stimulus abolishes the 10-a-second rhythm and substitutes one at 40–60 a second. Such resemblances in preparations of quite different structures may be quite fortuitous, but they make it difficult to resist the suggestion that the rhythms of the brain may be dependent on the general properties of cell masses rather than on any special anatomical arrangement of them. Whatever its origin, the 10-a-second rhythm of the cortex corresponds to the resting, drowsy, or inattentive state and there is no such uniform pulsation when the brain is alert.”. (shrink)

In Principles of Human Knowledge Berkeley speaks of the sensible qualities of an apple as being its parts. The paper argues that our words for sense-qualities play a role so unlike that of part-words that verbal atrocities would result from treating qualities as parts. Berkeley lends a surface plausibility to this move by focusing on a narrow selection of the normal linguistic accompaniment of the noun 'apple'. He puts out of mind the language of 'doing things with apples'— peeling, dicing, (...) and so on— which when recalled shows how strikingly far apart are the two categories he tries to mingle. (shrink)

The task of understanding Wittgenstein’s Philosophical Investigations is more like that of understanding a difficult person than of grasping difficult ideas. It makes heavy demands upon the reader. He must first of all have the patience to stare at slight variations in language-uses until they look as marked as Wittgenstein wants them to look. Then he must be prepared for what looks like impassable break-offs in line of thought. Next, if he is a philosopher, he must listen to a great (...) many hard sayings about philosophy—some of them prepared for, others thrown in as crotchety asides. Through all this, he must also come to see that here is suggested a radically new way of looking at language. Without some grasp of this new way, he cannot hope to feel the main force of the work. Instead of trying to summarize the Investigations, therefore, I will try to draw together some of the principal ideas which seem to me to give sense and unity to its details. This will not amount to seeing the book as a whole. Also, I expect that the result will misrepresent some of those ideas, I hope not grievously. (shrink)

The problem of consciousness arises when we accept that humans are subject to conscious experiences, and that these experiences resist explanations of a kind that other puzzling phenomena permit. I first consider the case that such experiences exist and then the reasons for taking a pessimistic view of our chances of explaining them. I argue that the fact that conscious experience is ineffable makes the problem even harder than Chalmers allows, as it undermines a presentation of the problem of reductive (...) explanation in this case. The fact that conscious phenomena require a first-person perspective provides a further reason for taking a pessimistic view of the chances for the kind of theory that Chalmers seeks. In a final section I consider what form solutions to the problem, as revised, might take. (shrink)