Philosophical Questions

Trying to puzzle out the most difficult and tangled questions of human existence marked one dimension of Renaissance thought and life. The discipline of moral philosophy lay at the heart of humanism’s rediscovery of antiquity, including its search for lost wisdom. Starting with Petrarch in the fourteenth century, humanists searched monastic libraries in Italy and beyond for manuscripts of forgotten classical works. Ancient philosophers such as Plato and Aristotle had been known only from medieval translations, commentaries, or citations, while others were virtually unknown. Poggio Bracciolini’s 1417 discovery of Lucretius’s On the Nature of Things precipitated the revitalization of Epicurean philosophy in Renaissance Europe. Lucretius’s materialism posed a challenge to Christian tenets such as the immortality of the soul.

Before the fall of Constantinople to the Ottomans in 1453, Byzantine Christian clergymen traveled to Italy for the Council of Florence in order to negotiate support for their church and government. They brought their most precious texts with them, including copies of Plato and the Neoplatonic Corpus Hermeticum. Florence became a flourishing center of Greek studies in the early to mid-fifteenth century, inspiring Marsilio Ficino’s translations of Plato and Hermetic writings that were later printed. Fresh encounters with ancient philosophy not only shed light on the classical world but also posed new questions for scholars and curious readers such as Leonardo to ponder. In his School of Athens (1509–1511), Raphael depicted Plato holding the Timaeus under his left arm, with his right hand gesturing toward the heavens, looking rather like Leonardo.

[J. G. Amato]

Titus Lucretius Carus, ca. 99–55 BCE

De rerum natura

Florence: Filippo Giunta, 1512

Barchas Collection PA6482 .A2 1512

Lucretius’s De rerum natura (On the Nature of Things) was vital to the rediscovery of Epicureanism in Renaissance Florence. Filippo Giunta (1450–1517) published the editio princeps of De rerum natura in 1512. With the editorial help of Michele Marullo (1458–1500), a Greek humanist, poet, and soldier, Lucretius’s text was printed with errors in the manuscript corrected. De rerum natura, a didactic poem written in the first century BCE, was intended to explain Epicurean philosophy to a Roman audience. In six books, Lucretius explores everything from atomism and the nature of human existence to ties between the human mind, the soul, and the cosmos. The combination of Epicurean physics and philosophy offered not only an understanding of the universe but also a formula for happiness based on conquering the fear of death and cultivating the management of pleasure (known in Greek as ataraxia).

In 1417, Poggio Bracciolini rediscovered Lucretius’s poem in a Benedictine library at Fulda. Although Leonardo never explicitly recorded this text in his lists of personal books, he cited the third book of Lucretius in a reference to Le cose naturali, a phrase that directly translates to De rerum natura. Learned Florentine humanists critically analyzed and debated Lucretius, and these heated conversations undoubtedly made Leonardo curious to read this ancient philosopher. The sophisticated and revolutionary ideas of this natural philosopher, particularly those on the relationship between the natural and the supernatural, fascinated Leonardo. It is through Lucretian thought and terms that Leonardo formulated his own progressive views of nature, cosmology, and philosophy.

[Rachel Ochoa]

Robert Grosseteste, ca. 1175–1253

Commentaria Roberti Linconiensis in libros posteriorum Aristotelis

Venice: Ottino di Luna, 1497

Rare Book Collection RBC KA1497 .G76

Gift of the Associates of the Stanford University Library

The painstaking notes that fill the margins of this volume indicate the seriousness of the (probably late sixteenth-century) student of Aristotle who owned it. The printed text consists of passages of Aristotle’s Posterior Analytics in large font, followed by extensive commentaries (in Latin) by two preeminent medieval English scholastic philosophers, Robert of Lincoln and Walter Burley. Both commentators died centuries before this edition was printed, and it was probably another century before the book fell into the hands of the devoted student whose annotations were, sadly, truncated when the book was rebound by a later owner. Luckily, the whimsical doodle on the inner cover, depicting the Roman emperor Tiberius, has been preserved.

This particular text was not actually in Leonardo’s library, but it exemplifies the role of medieval Aristotelian commentaries in his studies of natural philosophy. Despite his conceit of being able to encounter Nature herself without the mediation of book learning, Leonardo spent much time in his thirties studying the traditional authorities on the philosophical foundations of science. A severe language barrier obstructed him: he lacked basic fluency in Latin, in which almost all the great texts were written. Leonardo could gather hints of classical and medieval learning through Italian translations of medical texts and through Italian poetry that served as a repository of classical learning (e.g., the Divine Comedy). Aristotelian works were mostly untranslated, so Leonardo had to work hard to understand the foundational texts. In his notebooks he disparaged “abbreviators” like Grosseteste and Burley, but he still read them.

[Corey Dansereau]

Diogenes Laërtius, 180–240 CE

Delle vite de’ filosofi

Venice: Gratioso Perchacino, 1611

Rare Book Collection PA3965 .D7 I8

Gift of Dr. Leon Kolb

Diogenes Laërtius was a third-century Greek biographer of ancient philosophers. His Lives of the Philosophers provides forty-five biographies and is still considered an indispensable source for the history of Greek philosophy. Diogenes’s text is a compendium of ten books organized in two sections: Ionian (from Anaximander to Theophrastus and Chrysippus) and Italian (from Pythagoras to Epicurus). The Lives covers a range of topics: amusing gossip and scandalous stories, valuable biographical information, and concise overviews of philosophical doctrines.

Despite a resurgence of interest in the Greeks from the late fourteenth century onward, Diogenes’s text had a notable impact on humanist thought only after it became available in Latin. Translated from Greek by Ambrogio Traversari in 1433, the Latin version circulated widely in manuscript form and, after 1472, in print. The treatise helped Renaissance scholars such as Cristoforo Landino, commentator on Dante and translator of Pliny’s Natural History, to construct accounts of ancient philosophy. An Italian translation of Diogenes’s Lives appeared at the end of the fifteenth century, giving Leonardo access to otherwise inaccessible philosophical knowledge, as he struggled with learning Latin.

This 1611 lavishly illustrated Italian edition was printed a century after Leonardo’s lifetime. It represents a more advanced, standardized stage in the history of the printed book and showcases an abundance of beautiful woodcuts made from the paintings of the Venetian artist Giuseppe Porta. The illustrations depict the philosophers in detail, bestowing upon them an individualized identity by assigning them characteristic visual attributes that relate to their personal stories.

[Ron Reichman]