Corentin Tresnie

In 1583 the Italian botanist and physician Andrea Cesalpino (1524–1603) published De Plantis Libri XVI, considered to be the first treatise where botany is treated independently from medicine. In so doing, he broke with a long tradition inherited in Western science from Antiquity and perpetuated during the Middle Ages through the early Renaissance. At the same time, Cesalpino grounded his new approach in an original but well-informed interpretation of Aristotelian epistemology. This allowed the Italian philosopher to propose his own naturalistic teleology, as well as innovative uses of the old method of analogy. De Plantis laid the foundations of scientific systematics through a new focus on plant morphology and natural similarities and became a milestone in the history of Western botany. It is a precious testimony to the evolution of botanical and physiological knowledge in the Middle Ages and the Renaissance and illustrates the role of Aristotelian philosophy in 16th-century science.

While Neoplatonists have little to say on the topic of conflict and violence in their ethics or political philosophy, they use these concepts in order to discuss other issues. Plotinus considers violence as a way of testing one’s alignment with the cosmic order set by Providence. Porphyry and Iamblichus shift the emphasis to withdrawal from the body and universal cosmodicy, neutralizing the special role of violence. Proclus walks in their footsteps, but also gives a new epistemological meaning to conflict: civil war within the soul is a necessary condition for learning and doing philosophy.

Andrea Cesalpino (1519-1603) practised botany and medicine. Between the study of plants and the human body, he established a series of analogies based on the Aristotelian comparison of plants and animals from the point of view of the soul and that of Theophrastus from the point of view of anatomy of their parts. However, Cesalpino goes further than his ancient predecessors by linking the parts of plants to explanations in terms of functions. The nutrition, reproduction and growth of plants lead him to ask about the nature of their soul: do the totipotency of parts, the divisibility of plants, their plasticity and their ability to allow cuttings imply the divisibility of the soul of plants? These questions require the articulation of the metaphysics of the soul and a science of life and lead to the attribution of analogies between plants and humans three epistemic roles (descriptive, heuristic and problematic). _ Andrea Cesalpino (1519-1603) a pratiqué la botanique et la médecine. Entre l’étude des plantes et celle du corps humain, il établit une série d’analogies fondées sur la comparaison aristotélicienne des plantes et des animaux du point de vue de l’âme et celle de Théophraste du point de vue de l’anatomie de leurs parties. Toutefois, Cesalpino va plus loin que ses prédécesseurs antiques en liant les parties des plantes à des explications en termes de fonctions. La nutrition, la reproduction et la croissance des plantes le conduisent en effet à s’interroger sur la nature de leur âme : la totipotence des parties, la divisibilité des plantes, leur plasticité et leur faculté de bouturage impliquent-elles la divisibilité de l’âme des plantes ? Ces questions requièrent d’articuler la métaphysique de l’âme et une science de la vie et amènent à attribuer aux analogies entre les plantes et les hommes trois rôles épistémiques (descriptif, heuristique et problématique).

Cet article étudie le statut de la méthode de division par rapport aux autres partie de la dialectique selon le philosophe néoplatonicien Proclus, ainsi que les usages qu'il propose de cette méthode dans les différentes sciences qu'il distingue : mathématiques, physique, théologie. Proclus hérite en effet des conceptions divergentes de la division qu'on peut trouver dans les traditions (médio)platonicienne, aristotélicienne et stoïcienne. On constate à la fois une inconstance dans l'acception précise du terme de "division", et une cohérence générale dans l'acte qu'il désigne, à savoir une distinction entre des contenus (concepts, notions, propositions, hypothèses) ne disposant pas encore d'une définition scientifique.

Porphyry’s Life of Plotinus and Iamblichus’ Pythagorean Life display several passages in strong opposition to one another. At least in some significant cases, it is possible to show that the ethical stance adopted by each character corresponds to a position of his biographer about questions that divide Porphyry and Iamblichus. Thus, both texts can be considered as a way for these philosophers to implicitly make a point against each other, concerning matters such as the attitude one must have towards the body, one’s birth, health, passions and death; the possibility of the soul’s progression and liberation from the body; the traditional Greek religion and in particular rites of divination and sacrifice; and what makes a good philosophical education. These are all important issues of a long standing polemic between Porphyry and Iamblichus. While this does not make them mere mouthpieces, one should therefore take into account that the Plotinus and Pythagoras described in these texts carry important concerns of their authors, who carefully choose the episodes they narrate according to their agenda.