Immanuel Kant (1724-1804), the 18th century German proponent of the Enlightenment, was a latecomer on the scene. But for that, he captures much of the Spirit of the the period in his short essay, What is Enlightenment? The Enlightenment is, as he says, “man’s emergence from his self-imposed immaturity.” Kant, like the Enlightenment figures before him, sees the Enlightenment as requiring that individuals think for themselves. Or in his terse statement: “Sapere aude! Dare to use your own reason — this is the motto of the Enlightenment.”
By the time of Kant’s writing, philosophers had long been busy trying to do just that. Francis Bacon (1561-1626), Rene Descartes (1596-1650) and others had all been calling for individuals to overthrow what they saw as the yoke of their traditions and to reason for themselves. Bacon and Descartes both wrote in a time where the pressure of the past and the authority of the churches were still stronger than when Kant was writing. They thus in particular not only forged new way of approaching problems but also assailed the traditions that had become so oppressive. Bacon’s famous aphorism, which might serve as a motto for the Enlightenment as well as Kant’s, drives home both the rejection of the authority bound past and an orientation toward a more rational future: “Let not authority be truth, but truth be your authority.”
Bacon, like Descartes, and eventually Kant, all are searching for new ways to achieve truth, new ways to employ reason, without prejudice from the past. Bacon proposes a Novum Organon (a new tool or organ) that should allow us to evaluate the truth of our views independently of natural and culturally acquired biases that people may have. The inductive method that he proposes for advancing knowledge should proceed carefully from observation of phenomenon to explanatory hypotheses, which can be confirmed. On the basis of the then confirmed hypotheses, new observations might then be made and broader, more encompassing hypotheses formed and tested. So knowledge should progress.
While Bacon gives voice to the empiricist tradition that is important in the epistemology of the Enlightenment, Descartes is the first to develop a system of thought for the alternative rationalist tradition. In contrast to empiricists, who focus on empirical observations of phenomena, Descartes highlights the importance of reasoning. He proposes a system of philosophy in which we doubt all that we have been told and then reconstruct our worldview based solely on rational argument. His philosophy does not underline so much how he and others build on the advances of past thinkers. He viewed the thought of the Middle Ages and earlier periods of history as too compromised by dogmatism to be of much use for that. Instead, Descartes proposes that we examine each of our beliefs and accept as true only that which can be shown to be rationally justifiable.
In Enlightenment thinkers from Bacon and Descartes to Kant we see a desire to develop a new method for approaching knowledge and advancing it. Each of these thinkers contributes to the philosophical groundwork of the period of the Enlightenment. They paved the way for and in some cases made major contributions to the scientific revolution that is a hallmark of the Enlightenment period. More will be said about these Enlightenment philosophers later. But first I shall highlight a second fundamental shift in the thinking of the Enlightenment — namely the transition in political philosophy, which increasingly focuses on individual rights and underlines the value of democracy.
Go to the next section, on political philosophy during the Enlightenment.