I argue that Democritus presents a theory of colour in which the predominance of atomic shapes and microstructural arrangements are neces- sary but not sufficient for colour vision. Focusing primarily on Democritus’ basic colours, I analyse his microstructural account, providing a new analysis of the natural and technological underpinnings of his method of explanation. I argue that the notion of predominance allows Democritus to account for both the varia- tion and the repeatable correspondence of colour perception by setting limits on (...) possible microstructures. This account, however, is complicated by the evidence for a Democritean theory of colour transformation and distorted vision, which arise from a dynamic interplay of features at the level of microstructures and at the level of perception. (shrink)

I argue that Democritus presents a theory of colour in which the predominance of atomic shapes and microstructural arrangements are necessary but not sufficient for colour vision. Focusing primarily on Democritus’ basic colours, I analyse his microstructural account, providing a new analysis of the natural and technological underpinnings of his method of explanation. I argue that the notion of predominance allows Democritus to account for both the variation and the repeatable correspondence of colour perception by setting limits on possible microstructures. (...) This account, however, is complicated by the evidence for a Democritean theory of colour transformation and distorted vision, which arise from a dynamic interplay of features at the level of microstructures and at the level of perception. (shrink)

We begin with an analysis of the persuasiveness of assertibles and arguments in the texts and fragments of Ancient Stoicism, with a particular focus on those in which Stoic logic is presented as the tool to avoid the persuasiveness of sophisms and the Stoic sage as the one who can efface this persuasiveness by his expertise in dialectics. We then critically assess the contemporary consensus on the interpretation of these texts (notably in Chiaradona, Sedley and Tieleman), according to which Chrysippus (...) is interested in extra-logical forms of discourse. Tieleman further argues that Chrysippus uses persuasive premises for constructive purposes. We reject the thesis concerning Chrysippus' recognition of extra-logical truths, on the basis of the Stoic ideal of the sage, concluding instead that in Stoicism, (1) pithanon refers primarily to false assertibles, arguments and presentations and (2) the Stoic sage cannot be persuaded, but he can persuade his students in order to prepare their souls to receive the Stoic doctrines. (shrink)

Na primeira parte, fazemos um levantamento das ocorrências de pithanon (‘persuasivo’) e termos afins em textos e fragmentos do estoicismo antigo referentes à persuasão de asseríveis e argumentos e em textos e fragmentos em que a lógica estoica se apresenta como ferramenta para evitar a persuasão dos sofismas e o sábio estoico como aquele que capaz de vencer essa persuasão por sua perícia em dialética. Feito isso, consideramos criticamente as teses de Chiaradona, Sedley e Tieleman, para quem Crisipo está interessado (...) em formas extralógicas de discurso. Avaliaremos também a tese de Tieleman segundo a qual Crisipo usa premissas persuasivas para fins construtivos. Em nossas conclusões, descartamos a tese sobre o reconhecimento de verdades extralógicas por Crisipo com base no ideal do sábio estoico. Concluímos que, no estoicismo, (1) pithanon refere-se principalmente a falsas afirmações, argumentos e representações e (2) que o sábio estoico não pode ser persuadido, mas pode persuadir seus ouvintes a fim de preparar suas almas para receber as doutrinas estoicas. (shrink)

In this paper we will focus on the following points in Epictetus. First, we will concentrate our attention on the celebrated distinction between things up to us and things not up to us. Second, we will survey the distinction between the material and its use. According to this distinction, all external things are not up to us and consequently have no intrinsic value, although, as materials for the capacity of choice, their use has value, since humans can use things well (...) or badly. Third, we will demonstrate that the use of the materials corresponds to the use of presentations. Finally, we will present the three topics of Epictetus’ philosophy: the topic relative to desire, the topic relative to impulse and the topic relative to assent, being the first concerned with judgments about things and our desires; the second, about impulses and adequate actions; and the third, about assent and persuasiveness of presentations. The knowledge contained in these three topics constitute, for Epictetus, what we should know to make good use of presentations and, consequently, to achieve the human good, which is a capacity of choice according to nature that has at its disposal a comprehensive set of correct opinions about reality. (shrink)

The poiintt of Democritus' physiology of the eye is that vision occurs because the eye allows the image in, and its sponginess aids the transmission of the image to the reasoning faculty. Thus,, Democritus' ophthalmology plays an important, though neglected, part in his theory of vision.

_ The Concept of Presocratic Philosophy: Its Origins, Development and Significance _, by André Laks. Translated by Glenn W. Most. Princeton, NJ: Princeton University Press, 2018. Pp. x + 137.