A two strain HIV/AIDS model with treatment which allows AIDS patients with sensitive HIV-strain to undergo amelioration is presented as a system of non-linear ordinary differential equations. The disease-free equilibrium is shown to be globally asymptotically stable when the associated epidemic threshold known as the basic reproduction number for the model is less than unity. The centre manifold theory is used to show that the sensitive HIV-strain only and resistant HIV-strain only endemic equilibria are locally asymptotically stable when the associated (...) reproduction numbers are greater than unity. Qualitative analysis of the model including positivity, boundedness and persistence of solutions are presented. The model is numerically analysed to assess the effects of treatment with amelioration on the dynamics of a two strain HIV/AIDS model. Numerical simulations of the model show that the two strains co-exist whenever the reproduction numbers exceed unity. Further, treatment with amelioration may result in an increase in the total number of infective individuals (asymptomatic) but results in a decrease in the number of AIDS patients. Further, analysis of the reproduction numbers show that antiretroviral resistance increases with increase in antiretroviral use. (shrink)

The notion that our society, its education system and its intellectual life, is characterised by a split between two cultures – the arts or humanities on one hand, and the sciences on the other – has a long history. But it was C. P. Snow's Rede lecture of 1959 that brought it to prominence and began a public debate that is still raging in the media today. This 50th anniversary printing of The Two Cultures and its successor piece, A Second (...) Look features an introduction by Stefan Collini, charting the history and context of the debate, its implications and its afterlife. The importance of science and technology in policy run largely by non-scientists, the future for education and research, and the problem of fragmentation threatening hopes for a common culture are just some of the subjects discussed. (shrink)

The notion that our society, its education system and its intellectual life, is characterised by a split between two cultures – the arts or humanities on one hand and the sciences on the other – has a long history. But it was C. P. Snow's Rede lecture of 1959 that brought it to prominence and began a public debate that is still raging in the media today. This fiftieth anniversary printing of The Two Cultures and its successor piece, A Second (...) Look features an introduction by Stefan Collini, charting the history and context of the debate, its implications and its afterlife. The importance of science and technology in policy run largely by non-scientists, the future for education and research, and the problem of fragmentation threatening hopes for a common culture are just some of the subjects discussed. (shrink)

A number of biologists and philosophers have noted the diversity of interpretations of evolvability in contemporary evolutionary research. Different clusters of research defined by co-citation patterns or shared methodological orientation sometimes concentrate on distinct conceptions of evolvability. We examine five different activities where the notion of evolvability plays conceptual roles in evolutionary biological investigation: setting a research agenda, characterization, explanation, prediction, and control. Our analysis of representative examples demonstrates how different conceptual roles of evolvability are quasi-independent and yet exhibit important (...) relationships across scientific activities. It also provides us with the resources to detail two distinct strategies for how evolvability can help to synthesize disparate areas of research and thereby potentially serve as a unifying concept in evolutionary biology. (shrink)

Offering an original perspective on the central project of Descartes' Meditations, this book argues that Descartes' free will theodicy is crucial to his refutation of skepticism. A common thread runs through Descartes' radical First Meditation doubts, his Fourth Meditation discussion of error, and his pious reconciliation of providence and freedom: each involves a clash of perspectives-thinking of God seems to force conclusions diametrically opposed to those we reach when thinking only of ourselves. Descartes fears that a skeptic could exploit this (...) clash of perspectives to argue that Reason is not trustworthy because self-contradictory. To refute the skeptic and vindicate the consistency of Reason, it is not enough for Descartes to demonstrate that our Creator is perfect; he must also show that our errors cannot prove God's imperfection. To do this, Descartes invokes the idea that we err freely. However, prospects initially seem dim for this free will theodicy, because Descartes appears to lack any consistent or coherent understanding of human freedom. In an extremely in-depth analysis spanning four chapters, Ragland argues that despite initial appearances, Descartes consistently offered a coherent understanding of human freedom: for Descartes, freedom is most fundamentally the ability to do the right thing. Since we often do wrong, actual humans must therefore be able to do otherwise-our actions cannot be causally determined by God or our psychology. But freedom is in principle compatible with determinism: while leaving us free, God could have determined us to always do the good. Though this conception of freedom is both consistent and suitable to Descartes' purposes, when he attempts to reconcile it with divine providence, Descartes's strategy fails, running afoul of his infamous doctrine that God created the eternal truths. (shrink)

C P Ormell; Ideology and the Reform of School Mathematics, Journal of Philosophy of Education, Volume 3, Issue 1, 30 May 2006, Pages 37–54, https://doi.org/10.1.

: The principle of alternative possibilities (PAP) says that doing something freely implies being able to do otherwise. I show that Descartes consistently believed not only in PAP, but also in clear and distinct determinism (CDD), which claims that we sometimes cannot but judge true what we clearly perceive. Because Descartes thinks judgment is always a free act, PAP and CDD seem contradictory, but Descartes consistently resolved this apparent contradiction by distinguishing between two senses of 'could have done otherwise.' In (...) one sense alternative possibilities are necessary for freedom and in another they are not. I discuss three possible interpretations of the two senses. (shrink)

In an influential article, Anthony Kenny charged that (a) the view of freedom in Descartes’ “1645 letter to Mesland” is incoherent, and (b) that this incoherence was present in Descartes’ thought from the beginning. Against (b), I argue that such incoherence would rather support Gilson’s suspicions that the 1645 letter is dishonest. Against (a), I offer a close reading of the letter, showing that Kenny’s objection seems plausible only if we misconstrue a key ambiguity in the text. I close by (...) defending Descartes against some related worries of my own about the degrees of Cartesian freedom. I conclude that there is really no good reason to deny that Descartes’ view in the 1645 letter is both internally coherent and a genuine explication of the Meditations’ account of freedom. (shrink)

Dan Baras has recently argued for the claim that Theistic Mathematical Platonism fares no better than Mathematical Platonism with respect to explaining why our mathematical beliefs are correlated with mind-independent mathematical truths. In this paper I argue that, insofar as TMP provides a proximate or local explanation for this truth-tracking correlation whereas MP fails to offer any corresponding explanation, Baras’s claim that TMP fares no better than MP with respect to explaining this correlation is false.

In this interview, C. P. Goodman invites British Polanyi scholar Richard T. Allen to reflect on his interest in Polanyi’s philosophical ideas and share what he believes is valuable in his thought.

Current views of the control of complex, purposeful movements acknowledge that organizational processes must reconcile multiple concerns. The central priority is of course accomplishing the actor's goal. But in specifying the manner in which this occurs, the action plan must accommodate such factors as the interaction of mechanical forces associated with the motion of a multilinked system (classical mechanics) and, in many cases, intrinsic bias toward preferred movement patterns, characterized by so-called “coordination dynamics.” The most familiar example of the latter (...) is the symmetry constraint, where spatial trajectories and/or temporal landmarks (e.g., reversal points) of concurrentlymoving body segments (limbs, digits, etc.) exhibit mutual attraction. The natural coordination tendencies that emerge through these constraints can facilitate or hinder motor control, depending on the degree of congruency with the desired movement pattern. Motor control theorists have long recognized the role of classical mechanics in theories of movement organization, but an appreciation of the importance of intrinsic interlimb bias has been gained only recently.Although detailed descriptions of temporal coordination dynamics have been provided, systematic attempts to identify additional salient dimensions of interlimb constraint have been lacking. We develop and implement here a novel method for examining this problem by exploiting two robust principles of psychomotor behavior, the symmetry constraint and the Two-Thirds Power Law. Empirical evidence is provided that the relative spatial patterns of concurrently moving limbs are naturally constrained in much the same manner as previously identified temporal constraints and, further, that apparent velocity interference is an indirect, secondary consequence of primary spatial assimilation. The theoretical implications of spatial interference are elaborated with respect to movement organization and motor learning. The need to carefully consider the appropriate dimensions with which to characterize coordination dynamics is also discussed. (shrink)

ABSTRACT: René Descartes' Cogito is an example of a paradigmatic thought experiment, herald of both subjectivism and new science in Europe's Modern Age, that seems to have escaped the attention of thought experiment philosophers. On deep analysis, the Cogito appears as universal instantiation. The Cogito has strong rhetorical effects for it narratively generalizes from I to all human kind, and its historical and philosophical success can be explained from its concise enthymematic structure that rings true in many possible senses. We (...) consider it a preeminent example of a thought experiment as it states the power of thinking as its very contents. From Descartes' methodology of doubt we can conclude that, e.g., on a Wittgensteinian interpretation, the Cogito is a logical thought experiment rather than a psychological one. RESUMO: O Cogito de René Descartes é um exemplo de experimento mental paradigmático, precursor tanto do subjetivismo quanto da nova ciência, na Idade Moderna europeia, o qual parece ter escapado à atenção dos filósofos que estudaram o experimento mental. Na análise profunda, o Cogito aparece como uma instanciação universal. O Cogito tem fortes efeitos retóricos por si mesmo, generalizando narrativamente desde o eu para toda a espécie humana, e seu sucesso histórico e filosófico pode ser explicado por sua estrutura entimemática concisa, que soa através de muitos sentidos possíveis. Consideramos que é um exemplo proeminente de um experimento mental, na medida em que afirma o poder de pensar como seus próprios conteúdos. A partir da metodologia da dúvida de Descartes, podemos concluir que, em uma interpretação wittgensteiniana, o Cogito é um experimento mental mais lógico que psicológico. (shrink)

‘Epaphroditus’ is perhaps the commonest of Roman slave names apart from ‘Felix’, which it sometimes renders as a Greek equivalent. It is also used very extensively under the early empire by those with tria nomina, whether freedmen or freeborn, whether descendants of freedmen or not, whether citizens or Junian Latins. It is also found among decurions and even equestrians, but not senators. It thus has a non-elite resonance in the western half of the empire, but, like almost all personal cognomina, (...) not exclusively so. (shrink)

In conjunction with the Imperial status-indication, the Imperial nomina gentilicia provide the basic dating criterion for the Augusti liberti. Especially useful is the terminus ad quem, which is, in general, approximately 40 years after the death of the last possible manumitting emperor. Thus, the inscription of a Ti. Claudius Aug. lib. is not likely to be later than A.D. 100 and certainly not later than A.D. IIO.

In 163 Galen gave an anatomy lesson in Rome before an audience that included ‘Demetrius of Alexandria, a friend of Favorinus, who was every day speakingin public on themes proposed to him, in the style and manner of Favorinus’.

The principle of alternative possibilities (PAP) says that doing something freely implies being able to do otherwise. I show that Descartes consistently believed not only in PAP, but also in clear and distinct determinism (CDD), which claims that we sometimes cannot but judge true what we clearly perceive. Because Descartes thinks judgment is always a free act, PAP and CDD seem contradictory, but Descartes consistently resolved this apparent contradiction by distinguishing between two senses of 'could have done otherwise.' In one (...) sense alternative possibilities are necessary for freedom and in another they are not. I discuss three possible interpretations of the two senses. (shrink)

Herodotus has often been considered the Father of Ethnography no less than the Father of History. It comes as a paradox, then, that he has been taxed with confusion in his use of two terms that recur over and over in his discussion of peoples, θνος and γνος. Here is the formulation of Raymond Weil: Hérodote definit mal l‘ethnos’. C'est pour lui tantôot une subdivision du ‘génos’, tantôt au contraire un ensemble de ‘géné’. Ainsi 1' ‘ethnos’ des Médes, comme celui (...) des Scythes, groupe plusieurs γνεα. Mais cet ‘ethnos’ scythe porte aussi le nom de ‘génos’, et comprend des θνεα. Les Athéniens sont un ‘ethnos’ hellénique qui fait partie du ‘génos’ ionien, les Lacédémoniens un ‘ethnos’ pélasgique à rattacher au ‘génos’ dorien. (shrink)

We formalise the notion of those infinite binary sequences z that admit a single program P which expresses the entire algorithmical structure of z. Such a program P minimizes the information which must be used in a relative computation for z. We propose two concepts with different strength for this notion, the learnable and the super-learnable sequences. We establish three different equivalent characterizations of learnable (super-learnable, resp.) sequences. In particular, we prove that a sequences z is learnable (super-learnable, resp.) if (...) and only if there is a computable probability measure p such that p is Schnorr (Martin-Lof, resp.) p-random. There is a recursively enumerable sequence which is not learnable. The learnable sequences are invariant with respect to all total and effective transformations of infinite binary sequences. (shrink)

Between 1069, the year of his arrival at St. Martin in Mainz, where he spent the rest of his life in voluntary enclosure in a cell, and his death in 1082, the Irish monk Marianus Scottus dedicated countless hours to assembling the most sophisticated and comprehensive work on historical chronology that had ever been produced by a Latin writer up to that time. The fruits of his labors became a massive world chronicle, completed in 1076, whose most famous innovation consisted (...) in a far-reaching correction to the Christian, or “common,” era, which had been introduced by Dionysius Exiguus in the sixth century. Having compared the data of the Easter computus with the chronological parameters traditionally associated with the passion of Christ—the fifteenth day of the moon on Friday, 25 March—Marianus found that the only year in which the numbers could be made to fit was AD 12 rather than the traditionally accepted AD 34. As a result, he decided to predate the life of Jesus by twenty-two years, assigning his birth to the year corresponding to 22 BC. This gave rise to a new “corrected” era , which he used alongside its Dionysiac equivalent. (shrink)

Herodotus has often been considered the Father of Ethnography no less than the Father of History. It comes as a paradox, then, that he has been taxed with confusion in his use of two terms that recur over and over in his discussion of peoples, ἕθνος and γνος. Here is the formulation of Raymond Weil:Hérodote definit mal l‘ethnos’. C'est pour lui tantôot une subdivision du ‘génos’, tantôt au contraire un ensemble de ‘géné’. Ainsi 1' ‘ethnos’ des Médes, comme celui des (...) Scythes, groupe plusieurs γνεα. Mais cet ‘ethnos’ scythe porte aussi le nom de ‘génos’, et comprend des ἕθνεα. Les Athéniens sont un ‘ethnos’ hellénique qui fait partie du ‘génos’ ionien, les Lacédémoniens un ‘ethnos’ pélasgique à rattacher au ‘génos’ dorien. (shrink)