In The Heavenly City of Eighteenth-Century Philosophers, Carl Becker seeks to demonstrate that the great thinkers of the Enlightenment were far more in tune with the medieval “climate of opinion” than previously thought. He uses the words of St. Thomas Aquinas as a baseline for thirteenth century knowledge, and then goes on to draw comparisons to the works of the philosophes. Becker sees a predominately-Christian outlook in the foundations of the Enlightenment, such as references to “nature” and “natural law”, which he proposes are merely new terms for the attributes of the Christian God. He argues that much of the medieval mindset remains, only applied to new objects. In this way, Becker concludes that the Enlightenment merely substituted a new deity for the existing deity, and thus should be more correctly considered an example of medieval philosophy, not modern, as is typically the case. 

In presenting his argument, Becker often focuses on similar usages of a common word, “reason”, for example. Because both Aquinas and the philosophes claimed to appeal to reason, Becker insists that they were all speaking about essentially the same thing. When he accuses Enlightenment thinkers of clinging to “faith”, he treats their faith in the power of observation and experience no differently that the faith of a medieval theologian in the literal truth of the Bible. For Becker, the two are substantially identical, with the only distinction being in the objects of faith. Thus, eighteenth century philosophers “demolished the Heavenly City of St. Augustine only to rebuild it with more up-to-date materials”.

In 1957, some twenty-five years after the publication of Becker’s work, Peter Gay examined The Heavenly City in the June edition of The Political Science Quarterly, and found many things worth condemning. Gay is dismissive of Becker’s indictment of the philosophes based on their reliance on the ideas of earlier thinkers, saying, “…no era wholly liberates itself from its antecedents…” He also undercuts Becker’s analysis of similar language and concepts, noting that, “Words persist, but their meanings change…Rhetoric may change while ideas persist”, calling this “the trap of spurious persistence.” Gay goes on to accuse Becker of using reckless wordplay as evidence for an unsupportable premise, and of utilizing “indefensible” generalizations.

As to the charge that the Enlightenment was still Christian in its outlook, Gay concludes that the philosophes were more pagan than Christian, noting that many of their ideas could be traced to antiquity, not the Church. He also challenges Becker’s assertion that the philosophers of the eighteenth century clung to the “immortality of the soul”, counting Montesquieu, Diderot, Hume, Helvétius, Holbach and perhaps even Voltaire as unbelievers.

Gay defies any historian to accurately map the growth of the “natural law” tradition, comparing its development to “a map of the Nile Delta”, and insists that Becker, in his attempt at doing so, has “done a great deal to confuse the matter”. He says that Becker is wrong when he says that “natural law is essentially Christian” and then goes on to say that “Becker’s analysis of natural law is unphilosophical; his analysis of the relation of the philosophes [emphasis original] to history is unhistorical.” Gay also indicts Becker on a general lack of evidence, going so far as to impugn Becker’s motivation for his discoveries, attributing error to an intention to “debunk Enlightenment historians”.

When Peter Gay questions Becker’s integrity in this regard, it may seem harsh, but I believe that he is on to something. In "Everyman His Own Historian, " Becker presented historical knowledge as subjective and relative, with historians cast in the role of "story-tellers … to whom in successive ages has been entrusted the keeping of the useful myths." He claimed for the historian the responsibilty “to recreate imaginatively a series of events not present to perception…” so that the “special meaning” might appear.

Carl Becker was clearly not of the school of traditional historiography. With the discouraging year 1932 as a backdrop, he no doubt took issue with the presentation of the story of civilization as one of irrepressible and inevitable progress. One of the great temples of traditional history is the Enlightenment, and I believe that Becker, hoping to both shock his audience and to prod them into critically reassessing the Enlightenment, decided to put a torch to that temple.

Becker’s problem was that the facts did not entirely support his thesis, and as a result he was forced to bulldoze the landscape of eighteenth century thought in order to give his foundation at least the outward appearance of being level. He does this “bulldozing” by misinterpreting words and establishing definitions that don’t stand up under scrutiny. For example, Becker very early on (pgs. 14-19), defines “modern” thought as being characteristic of only the twentieth century so, in essence, he credits his generation with throwing off the shackles of superstition and religion. By establishing the twentieth century as the starting point of modern thought, he automatically consigns the eighteenth century to the preceeding era, the medieval. Becker identifies service to humanity as a Christian ideal, when clearly this is not so. By simply defining terms in a favorable light, Becker has already tilted the ground toward his argument.

Gay is quite correct in castigating Becker for his semantical gamesmanship. St. Thomas Aquinas used reason to validate the Church’s biblically ordained world view; if reality didn’t square with the “Holy Writ”, then the reality must be wrong, or at least misunderstood. The philosophes used reason to interpret the physical world, dismissed the authority of clerics and argued for observation and experience as the basis for truth, not the Church. David Hume’s On Miracles undercuts the legitimacy of the world’s religions, insomuch as they are dependent on miracles for their claims to divinity. To equate Hume with St. Thomas Aquinas because both spoke of reason is tantamount to saying that on January 30, 1933 Germany merely adopted a new national flag.

Another strong indication of the secular nature of the Enlightenment are the forces it unleashed. But Becker, in his quest to diminish the philosophes, seems quick to forget their intellectual children. Before the eighteenth century was finished, both the American Revolution, which raised republican virtue to nearly equal status with the Deity, and the religiously hostile French Revolution, would change the direction of the Western world. Becker deflects these proofs by stretching the term “religion” until it includes the “new religion of humanity” and allows for the “messianic enterprise” inherent in these overthrows of the old order. Again, Becker uses semantics to accomplish what evidence refutes.

The lack of sufficient footnotes in Becker’s work only adds to an overall impression of sloppy history that The Heavenly City creates. Again and again Becker throws out accusations without supplying ample evidence. He proposes that both Hume and Benjamin Franklin had a need for sanctification, but never tells us why he believes it. He insists that the philosophes needed God to order their universe, and that they had trouble admitting that there was evil in the world. Yet Voltaire presented a clear picture of senseless evil in Candide; how Becker draws the opposite conclusion he does not say. He repeatedly equates nature with God, and even goes so far as to say, “they [the philosophes] deified nature”, but provides no proof of this major buttress in his agrument.

An enduring irony of The Heavenly City is that Becker, the eighteenth century historian, does an excellent job in describing the intellectual atmosphere of the thirteenth century, but fails miserably when attempting to do the same for the time period in which he claims expertise. One must only conclude that the discrepancies are intentional, and that Becker is being duplicitous in making his case. It would appear that Becker’s enthusiasm for putting a torch to the temple of the Enlightenment exceeds his ability as a historian, or at least his commitment to historiographical integrity. This is unfortunate. It is, however, a useful lesson in what happens when one makes scholarship subordinate to historiographical bias.