The degree to which abundances are divided equitably among community species or evenness is a basic property of any biological community. Several evenness indices have been proposed to summarize community structure. However, despite their potential applicability in ecological research, none seems to be generally preferred. In this paper we show that, unlike other evenness indices without any clear information-theoretical meaning, Hill's parametric diversity measure E ,0 has an immediate relation to Rényi's generalized information. Therefore, E ,0 might be adequate for (...) summarizing community structure within the context of a general theoretical framework of diversity analysis based on information theory. (shrink)

Traditional diversity indices are computed from the abundances of species present and are insensitive to taxonomic differences between species. However, a community in which most species belong to the same genus is intuitively less diverse than another community with a similar number of species distributed more evenly between genera. In this paper, we propose an information-theoretical measure of taxonomic diversity that reflects both the abundances and taxonomic distinctness of the species. Unlike previous measures of taxonomic diversity, such as Rao's quadratic (...) entropy, in this new measure the analyzed taxonomic properties are associated with the single species instead of species pairs. (shrink)

According to the prevailing sentiment, changing the past is logically impossible. The prevailing sentiment is wrong. In this paper, I argue that the claim that changing the past entails a contradiction ultimately rests upon an empirical assumption, and so the conclusion that changing the past is logically impossible is to be resisted. I then present and discuss a model of time which drops the empirical assumption and coherently models changing the past. Finally, I defend the model, and changing the past, (...) against objections. (shrink)

In previous work I argued against (i) the likelihood of finding a theoretically sound foundation for the linked/convergent distinction and (ii) the utility of the distinction even if a sound theoretical basis could be found. Here I subject Douglas Walton’s comprehensive discussion of the linked/convergent distinction found in Argument Structure: A Pragmatic Theory to careful scrutiny and argue that at best Walton’s theory remains incomplete and that attempts to fill out the details will run afoul of at least one of (...) the problems adduced above—i.e., result in either a theoretically unsound distinction or a theoretically sound, but unnecessary distinction. (shrink)

G. C. J. Midgley; XIV—Linguistic Rules, Proceedings of the Aristotelian Society, Volume 59, Issue 1, 1 June 1959, Pages 271–290, https://doi.org/10.1093/aristot.

I.T. Oakley claims that the cogency of invalid, but cogent, arguments is context independent. Robert Pargetter and John Bigelow claim that the apparent cogency of any cogent, but invalid, argument is to be explained by the existence of a corresponding valid argument. I argue that both claims are incorrect and provide my own account of the cogency of arguments.

Despite a growing number of models argument for the logical possibility of changing the past there continues to be resistance to and confusion surrounding the possibility of changing the past. In this paper I shall attempt to mitigate the resistance and alleviate at least some of the confusion by distinguishing changing the past from what Richard Hanley calls ‘annulling’ the past and distinguishing both from what I shall call ‘otherwising’ the past.

With reference to recently proposed theoretical models accounting for reduction in terms of a unified dynamics governing all physical processes, we analyze the problem of working out a worldview accommodating our knowledge about natural phenomena. We stress the relevant conceptual differences between the considered models and standard quantum mechanics. In spite of the fact that both theories describe systems within a genuine Hilbert space framework, the peculiar features of the spontaneous reduction models limit drastically the states which are dynamically stable. (...) This fact by itself allows one to work out an interpretation of the formalism which makes it possible to give a satisfactory description of the world in terms of the values taken by an appropriately defined mass density function in ordinary configuration space. A topology based on this function and which is radically different from the one characterizing the Hilbert space is introduced, and in terms of it the idea of similarity of macroscopic situations is precisely defined. Finally, the formalism and the interpretation are shown to yield a natural criterion for establishing the psychophysical parallelism. The conclusion is that, within the considered theories and at the nonrelativistic level, one can satisfy all sensible requirements for a completely satisfactory macro-objective description of reality. (shrink)

The Buddhist philosophy of causality is primarily a theory (naya) of the human world. Its methodology, however, is objective and critical. It rejects the weight of mere authority or tradition, relies upon experience and reason, and emphasizes the critical examination and verification of all opinions. Although the Buddhist conception of knowledge and truth has a strong empirical and pragmatic bias (cf. Nyāya‐bindu 1.1), its conception of experience does not exclude introspection, rational intuition or mystical intuition (cf. Nyāya‐bindu 1.7–11). Although its (...) conception of reason creates a logical gulf between reason and experience, the gulf is bridged by a transcendental illusion (avidyā). Its employment of reason is highly analytical and it seeks to discover the ultimate elements constituting the structures of objects and experience. The constituent elements as the locus of causation are regarded as more real than their composite structures – dharma, dhātu or kṣana as contrasted with saṅghāta or santāna. At the same time, it raises dialectical questions and seriously considers the possibility of the empirical world being merely a working illusion. It discounts the apparent stability of objects, stressing their transience, finally defined as momentariness (see, for example, Ratnakīrti's Kṣaṇa‐bhaṅgasiddhi). It rejects the category of substance for that of process. Causality is thus regarded not as a dynamic interaction between substances, but as a functional, many‐one relationship of order characterized by invariance and uniformity within any given type of process. (shrink)

David Hitchcock, in his recent “Informal Logic and the Concept of Argument”, defends a recursive definition of ‘argument.’ I present and discuss several problems that arise for his definition. I argue that refining Hitchcock’s definition in order to resolve these problems reveals a crucial, but minimally explicated, relation that was, at best, playing an obscured role in the original definition or, at worst, completely absent from the original definition.

Dr. Leaf's article in the Journal of Hellenic Studies has recalled our attention to the venerable problem of the Rhesus. I hasten to give my adhesion to his main contention that the play is a pièce d'occasion justifying or sanctifying the foundation of the city of Amphipolis. But, as he remarks, seeing that the oracle ordering the removal of the bones of Theseus from Skyros to Athens preceded the actual removal by some years, so this play may be intended to (...) prepare for the actual removal of the bones of Rhesus from Troy by Hagnon, and may be prior to it by several years. For this official theft—doubtless arranged beforehand—we have only the authority of Polyainos' Strategemata, but it is a story which seems likely in itself, and goes far to explain the previously obscure lament of the Muse at the end of the play. My object is to examine the play afresh and see whether anything prevents our believing that it was written and exhibited somewhere near 440 B.C., in which case of course it is almost certainly the work of Euripides and not far from his Cyclops in date. (shrink)

In a previous article, I have attempted to summarize the evidence of Aristotle about the relations of Socrates and Plato in the development of the theory of Ideas. It may be of interest now to carry the enquiry further, and to see whether writers later than Aristotle have anything of importance to say about the whole question of the general intellectual relationship between the two men. In particular we must enquire whether or how far they regard or say anything to (...) lead us to regard the Dialogues of Plato as a record of Plato's own thought or as a biographical account of the thought of Socrates or—a third possibility—as both at the same time. And, in addition to this, we shall have to attempt some estimate of the value, if any, which we can put upon such statements—an estimate which would depend in its turn on our answer to the question how far they had access to original sources of information no longer extant. (shrink)

A brief review of the conceptual difficulties met by the quantum formalism is presented. The main attempts to overcome these difficulties are considered and their limitations are pointed out. A recent proposal based on the assumption of the occurrence of a specific type of wave function collapse is discussed and its consequences for the above-mentioned problems are analyzed.