Medieval Europe knew only two and a half dialogues of Plato
For centuries, Western scholars had direct access to just a sliver of Plato's writing. Then fifteenth-century Italy translated him wholesale, and in 1484 Marsilio Ficino published the complete works in Latin. Renaissance philosophy spent the next century trying to fit Plato, Aristotle and Christianity into one coherent picture.
Renaissance philosophy covers roughly 1400 to 1600, sitting between late medieval thinkers such as Aquinas and Ockham and the early modern era usually dated from Descartes's Discourse on Method in 1637. Much stayed the same. University teaching was still organised around Aristotle, with logic training the mind for natural philosophy, ethics and metaphysics. Physics lectures meant reading his Physics, and after the Reformation Protestant universities still taught ethics from his Nicomachean Ethics, publishing over fifty commentaries on it before 1682. The scholastic method of formal disputation, weighing the pros and cons of a question, also thrived.
What changed first was the range of sources. Alongside Plato, older schools returned: Michel de Montaigne revived ancient scepticism, and Justus Lipsius made Neostoicism fashionable, though Epicureanism was mostly caricatured and distrusted. All of them were read through a Christian filter that made them acceptable. Donato Acciaiuoli's 1478 commentary on Aristotle's ethics sold well largely because it blended the Aristotelian, Platonic and Christian traditions so smoothly.
The Italian humanists pushed back against scholastic jargon. Petrarch, who admired Plato without being able to read him, argued in his invective On His Own Ignorance that practical ethics mattered more than theory and that philosophy should use rhetoric to move people toward the good rather than merely uncover truth. In 1416 and 1417 Leonardo Bruni, chancellor of Florence, retranslated Aristotle's Ethics into flowing classical Latin so readers without technical training could follow it. Erasmus prepared a Greek edition of Aristotle, and university teachers had to at least appear to know Greek.
Humanists were initially cool on vernacular languages, but from the 1540s Italian was accepted as fit for philosophy, and Alessandro Piccolomini set out to translate or paraphrase all of Aristotle into it. Debates of the day ranged from free will, fought out between Erasmus and Martin Luther, to whether duelling could ever be justified, a question that produced a large sixteenth-century literature.
Source: Renaissance philosophy
