The Enlightenment as Methodology (Part One)

I wish that it were a “cliché” that the European movement called the “Enlightenment” (1650–1815) created the modern world. If that were universally acknowledged, then it would be a commonplace that the human faculty of reason must be credited with all that we call “modern progress.” 

That is the point Steven Pinker, leading neuroscientist, Johnstone Family Professor of Psychology at Harvard University, makes brilliantly, abundantly clear in his massive work of statistical compilation and analysis, explanation, and history, Enlightenment Now: The Case for Reason, Science, Humanism, and Progress (2018).

Science and scientific method, secularism (including separation of church and state), the economy of abundance built on economic liberalism (capitalism), respect for logic and evidence in thought and argument, recognition of the primacy of the individual and individual rights, political liberty, and constitutionally limited government: All make our world modern. All are the legacy of the Enlightenment.

And yet, what defines the Enlightenment is not ideas but methodology. That methodology is built on the primacy of human reason.

The Enlightenment, of course, did not discover and identify reason, which had a role in the Renaissance, the Reformation, and among the Scholastics—all earlier historical movements that evolved into the Enlightenment. But the Enlightenment, beginning in Europe in the seventeenth century and continuing through the eighteenth, valorized reason in all human endeavors and made it the passport to the modern world.

A barebones taxonomy of the historical movements that by the mid-seventeenth century (1650) had evolved into the European Enlightenment reveals a continuing core of reason.

Ancient Greek thought, culminating in the philosophy of Aristotle (384–322 B.C.), saw the birth of self-conscious reason, the method of logic, the theory of concepts, the understanding of the natural order in terms of natural law, and the application of reason to ethics, politics, and esthetics. One of his statements might have been the motto of the Enlightenment two millennia later: “It is the mark of an educated mind to be able to entertain a thought without accepting it” (The Metaphysics).

On this epic level of generality, Rome built its civilization and political empire on Greek philosophical foundations, notably the concepts of a rational natural order and natural law. Reason applied to human affairs—above all, the principle of law applied to all Roman citizens (with the fatal anomaly of slavery)—built and sustained the Roman empire for more than 1,000 years.

Perhaps the complexity of what ensued—for our purposes at least—can be left to this sweeping summary by the Encyclopedia Britannica:

Amid the turmoil of empire, however, a new concern arose for personal salvation, and the way was paved for the triumph of the Christian religion. Christian thinkers [centuries later] gradually found thought known as Scholasticism, culminating in the work of Thomas Aquinas, that resurrected reason as a tool of understanding. 

The church never abandoned Greek philosophy; early church fathers like Augustine were Neoplatonist, the school of the late Roman thinker Plotinus. His structure was more conducive to the church’s cosmology than was Aristotelianism. “The three basic principles of Plotinus’s metaphysics are called by him ‘the One’ (or, equivalently, ‘the Good’), Intellect, and Soul. . . . These principles are both ultimate ontological realities and explanatory principles.”

The chief lesson for us is that Christianity after more than a millennium found its way back to the methodology of reason. Late medieval Scholasticism (the thirteenth and early fourteenth centuries) came under the influence of Aristotle’s ideas, which had persisted in the Islamic world in the work of philosophers such as Averroes and Avicenna.

Again, on an epic plane: the philosophy and rule of Christianity, accepted as eternal and unchangeable in the Middle Ages, finally weakened when Thomas Aquinas (1225–1274), greatest of the Scholastics, inspired by rediscovery of the works of Aristotle, argued that reason is the key to the natural order and faith to the divine order.

(In time, his philosophy became the official doctrine of the Church of Rome. “In 1879, the papal bull Aeterni Patris endorsed . . . Aquinas’s theology . . . as an authentic expression of doctrine and said it should be studied by all students of theology.”)

The entire evolution of ideas about reason and how to apply it focused in no small measure on the issue of “universals.” If there are sets or groups or classes of particulars— red, dog, apple—what is the same about them? Every concrete instance of “red,” every dog, is different, if only slightly.

Plato gave an answer never forgotten—and never agreed upon. Part of each particular in a set or class is a universal, an abstract entity that lends sameness. There is “green” in every green thing. This is the theory called “realism”—universals are real existents in some realm of forms.

Starting with Aristotle, and continuing through the Roman Stoics, the Neoplatonists, the early churchmen, and the Scholastics, the argument over the nature of universals—that is, the referents of our concepts and words—never flagged. The chief theory rivaling Platonic realism was “nominalism” (which acquired that name much later from the French theologian Roscellinus [1050–1125])—the theory (in many variants) that a concept is just a name for a given group of entities. There are only concretes, not “universals,” and the names we give groups, sets, and classes of concretes.

Only in the fifteenth century, however, was nominalism explicitly identified as a unified theory about concepts. Peter Abelard and William of Ockham represent the full, final expression of nominalism within the Scholastic tradition.

With the breakup of temporal power of the Catholic Church, Aristotle’s realism (a modification of Platonic realism) did not dominate the scientific revolution or the Enlightenment (Thomas Hobbes revived nominalism in modern—Enlightenment— philosophy). Still later, John Stuart Mill gave a pithy summary, writing “there is nothing general except names.”

Because the agenda of science is to reach demonstrable generalizations about classes of things, to discover how they act under specified conditions and interact with other things—and why—the new scientific revolution could not proceed on the premise of extreme nominalism. Yet, no single theory of concepts widely and explicitly identified as the philosophical foundation of science’s vast structure of generalizations ever has emerged. 

The Roman Catholic Church had sustained intellect, scholarship, philosophy, libraries, and the very concept of Europe for an incredible fifteen  centuries, from the 380 B.C. declaration of Catholicism as the official religion of the Roman empire to the beginning of the Protestant Reformation. Across the vast, savage forests of Europe, with its barbarian tribes and wars, assaults by Islam, and the awful “night” of superstition and barbarism, the church by unrelenting efforts, personal sacrifices, and bravery of its adherents had “kept it all together”—sustained mind, learning, moral order, and a kind of moral dominance over even barbarian kings by virtue of its awe-inspiring steadfastness of faith.     

But Europe had exhausted medieval Scholasticism and came to the vestibule of the intellectual movements that culminated in the Enlightenment and the modern world we know: the Renaissance, the scientific revolution, humanism, and the Protestant Reformation.