The Renaissance

Medieval philosophy had culminated in the achievements of scholasticism, a grand system of thought developed by generations of patient scholars employing neoplatonic and Aristotelean philosophy in the service of traditional Christian theology. But by the end of the fifteenth century, confidence in the success of this enterprise had eroded, and many thinkers tried to make a fresh start by rejecting such extensive reliance on the authority of earlier scholars. Just as religious reformers challenged ecclesiastical authority and made individual believers responsible for their own relation to god, prominent Renaissance thinkers proposed an analogous elimination of all appeals to authority in education and science.

Educational practice was revolutionized by the recovery of ancient documents, the rejection of institutional authority, and renewed emphasis on individual freedom. The humanists expressed an enormous confidence in the power of reason as a source of profound understanding of human nature and of our place in the natural order. Giovanni Pico della Mirandola’s Oration, for example, held forth the possibilities for a comprehensive new order of knowledge relying on human understanding without reference to divine revelation. For some, like Desiderius Erasmus and Marsillio Ficino, this spirit found expression in a return to careful study of classical texts in their own right, without relying on centuries of scholastic commentary. But for more revolutionary thinkers as diverse as Giordano Bruno and Francisco Suárez, humanism offered an opportunity to incorporate modern developments along with classical elements in entirely new systems of metaphysical knowledge.

The rise of the new science also offered a significant change in the prospects for human knowledge of the natural world. Copernicus argued on theoretical grounds for a heliocentric view of the universe, for which Kepler provided a more secure mathematical interpretation. Galileo contributed not only an impressive series of direct observations of both celestial and terrestrial motion but also a serious effort to explain and defend the new methods. By abandoning explanation in terms of final causes, by emphasizing the importance of observation, and by trying to develop quantified accounts of all, renaissance scientists began to develop the foundations of a thoroughly empirical view of the world.

This emerging emphasis on empirical methods permanently transformed study of the natural world. Making extensive use of sensory observations made possible by the development of new instrumentation fostered an urge to seek quantification of every phenomenon. There were exceptions like Herbert of Cherbury, who hoped that the natural light of common notions imprinted innately in every human being would provide perfect certainty as a foundation for Christianity. But most of the moderns gladly embraced the methods, style, and content of the new science.

The Skeptical Challenge

While the Renaissance encouraged abandonment of the benefits of scholastic learning, it could offer only the promise that new ways of thinking might one day suitably replace them. Along with high hopes for the achievement of human knowledge came significant doubts about its possibility. By recovering and translating the work of Sextus Empiricus, humanist scholars introduced the tradition of classical skepticism as an element of modern thought. Turning the power of reasoning against itself at every opportunity, the Pyrrhonists proposed that we suspend all belief whenever we find ourselves capable of doubting the truth of what we suppose. The trouble is that very little beyond immediate personal experience can pass this test of indubitability.

The greatest exponent of modern Pyrrhonism was Michel de Montaigne, whose Essays (1580, 1588) gave prominent place to skeptical arguments. Any attempt to achieve knowledge is misguided, on his view, because it arrogantly supposes that the natural world and everything in it exists only for the satisfaction of our idle curiosity. Since the evidence of our senses is notoriously liable to error and the reliability of logical reasoning cannot be demonstrated without circularity, we would indeed be better off to doubt everything and rest comfortably with mere opinion. Even the new science offers no hope, Montaigne argued, since it must eventually be surpassed in the same way that it has overcome the old. These concerns created a challenge to which modern philosophers were bound to respond.

The Central Questions

Against the background of humanistic scholarship, the rise of the new science, and the challenge of skepticism, modern philosophers were preoccupied with philosophical issues in several distinct areas:

• Epistemology: Can human beings achieve any certain knowledge of the world? If so, what are the sources upon which genuine knowledge depends? In particular, how does sense perception operate in service of human knowledge?
• Metaphysics: What kinds of things ultimately compose the universe? In particular, what are the distinctive features of human nature, and how do they function in relation to each other and the world at large? Does god exist?
• Ethics: By what standards should human conduct be evaluated? Which actions are morally right, and what motivates us to perform them? Is moral life possible without the support of religious belief?
• Metaphilosophy: Does philosophy have a distinctive place in human life generally? What are the proper aims and methods of philosophical inquiry?

Although not every philosopher addressed all of these issues and some philosophers had much more to say about some issues than others, our survey of modern philosophy will trace the content of their responses to questions of these basic sorts.

British politician and entrepreneur Francis Bacon, for example, expressed the modern spirit well in a series of works designed to replace stultified Aristotelianism with improved methods for achieving truth. Assuming that the difficulties we experience are invariably the results of poor training and can therefore be eliminated, Bacon promised that the adoption of more appropriate habits of thinking will enable individual thinkers to transcend them.

Believing that the first step toward knowledge is to identify its major obstacles, Bacon took note of four distinct varieties of distractions that too often prevent us from understanding the world correctly:

• Idols of the Tribe, which arise from human nature generally, encourage us to over-estimate our own importance within the greater scheme of things by supposing that everything must truly be as it appears to us.
• Idols of the Cave, which arise from our individual natures, lead each one of us to extrapolate inappropriately from his or her own case to a hasty generalization about humanity, life, or nature generally.
• Idols of the Marketplace, which arise from the use of language as a means of communication, interfere with an unbiased perception of natural phenomena by forcing us to express everything in traditional terms.
• Idols of the Theatre, which arise from academic philosophy itself, produces an inclination to build and defend elaborate systems of thought that are founded on little evidence from ordinary experience.

Once we notice the effects that these “Idols” have upon us, Bacon supposed, we are in a position to avoid them, and our knowledge of nature will accordingly improve. In a more positive spirit, Bacon proposed a patient method borrowed from the practice of the new scientists of the preceding generation. First, we must use our senses (properly freed from the idols) to collect and organize many particular instances from experience. Resisting the urge to generalize whenever it is possible to do so, we adhere firmly to an experimental appreciation of the natural world. Only when it seems unavoidable will we then tentatively postulate modest rules about the coordination and regularity we observe among these cases, subject always to confirmation or refutation by future experiences.

Thomas Hobbes

Even more than Bacon, Thomas Hobbes illustrated the transition from medieval to modern thinking in Britain. His Leviathan effectively developed a vocabulary for philosophy in the English language by using Anglicized versions of the technical terms employed by Greek and Latin authors. Careful use of words to signify common ideas in the mind, Hobbes maintained, avoids the difficulties to which human reasoning is most obviously prone and makes it possible to articulate a clear conception of reality (Leviathan I 4).

For Hobbes, that conception is bound to be a mechanistic one: the movements of physical objects will turn out to be sufficient to explain everything in the universe. The chief purpose of scientific investigation, then, is to develop a geometrical account of the motion of bodies, which will reveal the genuine basis of their causal interactions and the regularity of the natural world. Thus, Hobbes defended a strictly materialist view of the world.

Human Nature