I love his analysis.
>By starting at 1400, the graph misses the great age of classical philosophy, but there was no point in starting earlier. The spike in –4C is so dominant that everything after 1400 is flat—and no wonder. Take Socrates, Plato, and Aristotle, add major figures such as Heraclitus, Parmenides, Anaxagoras, Protagoras, Democritus, and Epicurus, then add the lesser but still significant figures, bunch most of them into a century and a half during –5C and –4C in a Europe that had a population somewhere around 20 million, and you have an accomplishment rate in European philosophy that will dwarf anything that comes after.
>1. The last half of the 1600s provided the philosophical underpinnings of the Enlightenment. Descartes and Bacon had been precursors in the first half of the century. Then, clustered into a few decades, came Hobbes, Pascal, Leibniz, Spinoza, and Locke.
>2 The last two-thirds of the 1700s saw the culmination of the Enlightenment in Montesquieu, Helvetius, Hume, Rousseau, Diderot, and Voltaire and—so close in time that they form one spike in the graph—the philosophers who would set the stage for 19C, Moses Mendelssohn, Condorcet, Herder, Fichte, Bentham, and, towering over all, Kant.