At the end of the 20th century, Jacques Barzun, now more than a century old himself, wrote "From Dawn to Decadence, 500 Years of Western Cultural Life, 1500 to the Present." "It takes only a look at the numbers to see that the 20th century is coming to an end. A wider and deeper scrutiny is needed to see that in the West the culture of the last 500 years is ending at the same time."

This series of columns will examine the roots, causes and consequences of the ideas that are at the heart of this Modern Age. As will become clear, it is not possible to understand the sweep of the history of the West without understanding religious thinking and religious philosophy and the reaction to and accommodation of such thinking. For example, though profoundly different, both the American and French Revolutions were consequences of the Enlightenment. But the Enlightenment, in and of itself, was also deeply revolutionary in its rejection of the Age of Faith that preceded it.

Jonathan I. Israel describes the Enlightenment in his massive work, "Radical Enlightenment, Philosophy and the Making of Modernity 1650-1750." "During the later Middle Ages and the early modern age down to around 1650, western civilization was based on a largely shared core of faith, tradition, and authority. By contrast, after 1650, everything, no matter how fundamental or deeply rooted, was questioned in the light of philosophical reason and frequently challenged or replaced by startlingly different concepts."

Israel informs us that prior to the middle of the 17th century, Europe was overwhelmingly a culture devoted to God. That is, "it was a civilization in which almost no one challenged the essentials of Christianity or the basic premises of what was taken to be a divinely ordained system. By contrast, after 1650, a general process of rationalization and secularization set in which rapidly overthrew theology's age-old hegemony in the world of study, slowly but surely eradicated ... belief in the supernatural from Europe's intellectual culture, and led a few openly to challenge everything inherited from the past — not just commonly received assumptions about mankind, society, politics, and the cosmos, but also the veracity of the Bible and the Christian faith or indeed any faith."