Recent study of Galileo's surviving manuscript notes on motion has revealed that by 1609 he had developed the major part of his theory of projectile motion. During the period of these theoretical advances Galileo was engaged in important related experimental investigations; this has become clear from the study of folios 114r and 116v of the manuscript on motion. This paper provides an interpretation of a manuscript not previously discussed—folio 81r. The analysis provided indicates that it is evidence of an important (...) early experiment of the series in which Galileo studied the projectile trajectory. The reconstruction of the experiment concerned reveals relationships with the enquiries suggested by folio 114r and 116v and indicates that Galileo examined the form of projectile trajectories with some care. (shrink)

The existence of consciousness in animals may have been overlooked. Continuity in consciousness between humans and animals is predicted by evolutionary theory. However, there are specific methodological difficulties associated with investigating such a phenomenon: it cannot be directly measured; animals, unlike humans, cannot directly tell us about their conscious experience; experiments which have made comparisons to human consciousness cannot detect consciousness of a different form; application of the law of parsimony in science has traditionally led to the conclusion that it (...) does not exist. (shrink)

Many have adopted the view that informal logic is importantly dependent on epistemology . Finocchiaro has raised this issue in the context argumentation theory, as perhaps distinguished from informal logic A recent pair of issues of Informal Logic , guest edited by Christoph Lumer, was devoted to epistemological approaches to argumentation. On the other hand, both Johnson and Blair and Johnson have expressed reservations. In this paper I want to take another look at the relationship between informal logic and epistemology. (...) I will argue that there are reasons for skepticism regarding the Received View that have not been taken into consideration and fully appreciated by those who advocate some form of this view. (shrink)

Summary One aim of this paper is to provide an assessment of the recent attempts to interpret the development of Galileo's theory of motion in the late Paduan period 1604?1610. In addition to this a new interpretation of this process of development is advanced. This interpretation is the first that proves able to provide a full account of all the features on folio 152r of volume 72 of the Galilean manuscripts which has been claimed to be of crucial significance. The (...) major feature of the interpretation is that it is the first to account for the relationship between Galileo's theoretical and experimental work in the period 1604?1610. (shrink)

This is a companion paper to my preceding one on Harriot's experimentations in the field of the sign-rule of multiplication in algebra. Cardano had earlier attacked the conventional rule in a chapter of his De Aliza regula liber, published in 1570 as an appendix to the second edition of his Ars magna. He returned to the subject in a brief tract, published nearly a century later in his collected works as Sermo de plus et minus. Only Cardano's valid contention that (...) the standard ‘proof’ of the accustomed sign-rule was faulty made impact, in the Euclidean background to which the ‘proof’ belonged. His cause was to preserve the purity of the Euclidean tradition. It overshadows the true aim in the De Aliza chapter, but the Sermo reveals it plainly as far from retrograde: he wished to retain all the new techniques of algebra that brought in not only ‘minus’ quantities but also their square roots, and to escape the ‘impossible’ status of these last. This the rebel sign-rule did for him by making every root of a ‘minus’ just another ‘minus’. (shrink)

This work presents a systematic study of decision problems for equational theories of algebras of binary relations (relation algebras). For example, an easily applicable but deep method, based on von Neumann's coordinatization theorem, is developed for establishing undecidability results. The method is used to solve several outstanding problems posed by Tarski. In addition, the complexity of intervals of equational theories of relation algebras with respect to questions of decidability is investigated. Using ideas that go back to Jonsson and Lyndon, the (...) authors show that such intervals can have the same complexity as the lattice of subsets of the set of the natural numbers. Finally, some new and quite interesting examples of decidable equational theories are given. The methods developed in the monograph show promise of broad applicability. They provide researchers in algebra and logic with a new arsenal of techniques for resolving decision questions in various domains of algebraic logic. (shrink)

The reputation Theologoumena Arithmeticae has acquired is largely that of being an odd, and frequently opaque, compilation of arithmological lore. As a sourcebook for this aspect of the Pythagorean tradition it is, of course, invaluable. However, its poor reputation is increased, and its historical value lessened, by the depredations time has wrought on the text. ThA was never great prose: it is a compilation, largely from the lost Theologoumena Arithmeticae of Nicomachus of Gerasa and from Anatolius' Peri Dekados; and the (...) text which cannot be safely or conjecturally assigned to these two sources often reads like little more than the written-up notes of some student. However, the treatise contains passages of considerable lucidity, within the context of its peculiar framework. (shrink)