Name der Zeitschrift: Archiv für Geschichte der Philosophie Jahrgang: 97 Heft: 2 Seiten: 135-159.

In the Timaeus, Plato says that the hypothesis of there being five worlds casts a reasonable doubt. Neither ancient commentators of Plato nor modern scholars have succeeded in unveiling the meaning of this hypothesis. I propose that five is the number of combinations with which the five platonic solids can be arranged in sets of four, each set making up a world. I discuss the question of whether Plato's mathematical skills made him equal to the task of calculating the correct (...) number of combinations, as well as the possible reasons why he rejected the hypothesis of there being five worlds. (shrink)

In the Timaeus Plato says that, among the infinite number of right-angled scalene elementary triangles, the best is that ἐξ οὗ τὸ ἰσόπλευρον ἐκ τρίτου συνέστηκε. Apart from few exceptions to be mentioned shortly, the translations of the Timaeus, which I am aware of spanning the period from the second half of the nineteenth century up to recent times, have usually rendered this passage as meaning that such an elementary triangle is that which, when two are combined, the equilateral triangle (...) forms as a third figure. For instance, Bury and Zeyl respectively translate: out of which, when two are conjoined, the equilateral triangle is constructed as a third. and from [a pair of] which the equilateral triangle is constructed as a third figure. I shall refer to this sort of translation as the Prevailing Translation. (shrink)

Journal Name: Apeiron Issue: Ahead of print.

It is a notion commonly acknowledged that in his work Timaeus the Athenian philosopher Plato (_c_. 429–347 BC) laid down an early chemical theory of the creation, structure and phenomena of the universe. There is much truth in this acknowledgement because Plato’s “chemistry” gives a description of the material world in mathematical terms, an approach that marks an outstanding advancement over cosmologic doctrines put forward by his predecessors, and which was very influential on western culture for many centuries. In the (...) present article, I discuss inter-transformations among Plato’s four types (fire, air, water, and earth) as well as the interpretation they received in the literature. I find that scientists and scholars generally emphasized (and often misunderstood) mathematical aspects of these “reactions” over the philosophical ones. I argue that Plato’s “chemistry” in fact bears on crucial topics of his philosophical system, such as Forms, Becoming, causation and teleology. I propose that consideration of these doctrines help to understand not only the sense of his “chemical” reactions, but also the reason why their stoichiometry is by surface balance and is restricted only to types that come to be and pass away but not to those that provoke the inter-transformations. (shrink)

This paper tries to demonstrate that some passages of Pliny's Naturalis historia on metallurgical materials are influenced by the Stoic philosopher Posidonius' view that surfaces possess a physical existence. Indeed, Pliny reports that copper surfaces are material, both acting towards drawing a patina to themselves, and being acted upon; i.e. they are both chemically modified by air and fire, and subject to mechanical removal. Also relatable to Posidonius, namely to his view of the interaction between soul and body, is Pliny's (...) account of lead and tin, which can be united thanks to the action they mutually exert on each other, since each metal holds together both itself and what is outside itself. A further influence from the ‘aetiologist’ Posidonius is also betrayed in the care Pliny exercises in describing not only metal corrosion and soldering, but also their causes. Both the scientific and the philosophical imports of these passages are compared with passages by Plato and Plutarch on metallurgical subjects; they are also discussed in the light of the theories on ‘mixture’ propounded by Aristotle and by the Old Stoics. It is shown that Pliny's account compares favorably with Posidonius' doctrine, whereas it is at striking variance with the other ancient reports. Introduction Philosophical and literary evidence 2.1 Pliny 2.2 Posidonius 2.3 Plato and Plutarch Discussion Conclusion. (shrink)

This paper analyzes views of the Stoic philosopher Posidonius (1st century BC) in the light of modern Chemistry. I propose that Posidonius’ account on “generation and destruction” bears noteworthy similarities to the scientific notions of chemical elements, chemical species, nuclear reactions, and the law of conservation of mass. I find that his views compare favorably also with our understanding of chemical change at solid surfaces. Provided his thought is correctly placed in the cultural context of his day, I argue that (...) Posidonius deserves a previously un-acknowledged consideration in the historical background of modern Chemistry. (shrink)