Somewhere on the internecks, I engaged in a discussion of the origins of the “double truth” theory. I wish I could find it again (let me know if you know), but I was asked where the doctrine arose. I have done a little digging, and this is a report on that.
The “double truth” theory is roughly this:
If you use reason, then you will be led to a number of conclusions (where “reason” is the use of evidence and logic of various kinds).
If you rely on faith and revelation, which is the source of knowledge of the things of God, etc., then you may be led to a number of different conclusions.
These are the two truths, and the relationship between them is the subject of much debate in theology (not so much in philosophy, and almost not at all in science). Some have held that the truths of faith must agree with the truths of science, because God is author of both, and so any apparent conflict shows that we have failed to understand one or the other. Some (like Luther in his more excitable moments) have held that faith always trumps reason. Some have held that science must trump faith (if religion is to apply in the modern world). And so on. Some take a misquoted slogan of Tertullian’s and argue that we should hold to faith because it is absurd according to reason (a view he did not hold).
So, where does this come from?
It appears to have been based on, but is not found in, the work of Averroes (Abu’l Walid Muhammad Ibn Rushd Al-Qurtubi) in Spain and northern Africa, around the latter part of the 12th century, in response to the increasingly “fundamentalist” views of Islamic scholars against secular science, which had flourished until that time, but which was eclipsed by the Almohad Dynasty and its rejection of the liberalism of the Almoravids they supplanted. Ibn Rushd was regarded by early western scholars of the revival that followed shortly afterwards as “the Commentator” of Aristotle (“the Philosopher”), and his views found a willing champion in Siger of Brabant, who was a prominent Averroeist in Paris. Siger held to a view that reason and faith would deliver different conclusions and taught an unreconstructed Aristotle to the students at the Sorbonne.
A parody of his views, most likely introduced to combat his political influence between the “nations” of the Sorbonne (France, Normandy, Picardy, and England) and to assert the primacy of the Theology faculty over the faculties of Arts, Medicine, and Law (Arts then, as now, had the lowest rank. Some things never change), was issued in a Condemnation in 1270 by the Bishop of Paris, Étienne Tempier. Tempier issued a second Condemnation in 1277 in which Siger was a key target, and the notion of double truth banned from teaching (effectively defeating Averroeism): “as if there were two contrary truths, and as if against the truth of Sacred Scripture, there is truth in the sayings of the condemned pagans.”
Of course, nobody held the views Tempier denounced, but it was enough to have Siger and others banned from teaching and sent into exile. But at the same time, Thomas Aquinas was writing his various Summas, and in them he noted that faith and reason do not always agree, and held that faith perfects reason (Summa Theologica Prima Pars, Question I, Article 8; Summa contra Gentiles 1.7.6-7), rather than supplants it. He wrote in the latter reference:
Now, although the truth of the Christian faith which we have discussed surpasses the capacity of the reason, nevertheless that truth that the human reason is naturally endowed to know cannot be opposed to the truth of the Christian faith. For that with which the human reason is naturally endowed is clearly most true; so much so, that it is impossible for us to think of such truths as false. Nor is it permissible to believe as false that which we hold by faith, since this is confirmed in a way that is so clearly divine. Since, therefore, only the false is opposed to the true, as is clearly evident from an examination of their definitions, it is impossible that the truth of faith should be opposed to those principles that the human reason knows naturally.
Shortly afterwards, the doctrine also found its way into Jewish thought, via Isaac Albalag.
Aquinas’ writings became effectively canonical for Catholic orthodoxy, and as a result, the Condemnation of 1277 was rescinded. Thereafter the doctrine that truth cannot contradict truth held sway, and it still does. The accommodation that the Catholic church has reached via Aquinas is that when no spiritual doctrine is at risk, one should always accept the truth of a scientifically successful theory (in the same manner that a scientist would, provisionally and according to empirical adequacy). When a spiritual doctrine is at risk, as when someone might claim that whatever “soul” refers to it evolved as a disposition of brains, then the doctrine takes priority, but in truth, the doctrine is reinterpreted so as not to conflict with the science. An example I like to reference is given in Harry Paul’s book – attacks on Daltonian chemistry, which contradicted the form-substance theory of Aristotle on which the doctrine of Transsubstantiation was based, developed over time into a redefinition of terms like “form” and “substance” to permit atomistic accounts, reluctantly.
As Harnack spent so much energy demonstrating, dogma is a dynamic and fluid thing, always adapting to the social and intellectual conditions in which it finds itself. We have a rather foreshortened view of this history today, because we are used to conservatives and literalists trying to change the conditions rather than adapt, but even today the bulk of western religion adapts to scientific thinking in one way or another.
Paul, Harry W. 1979. The edge of contingency: French Catholic reaction to scientific change from Darwin to Duhem. Gainesville: University Presses of Florida: A University of Florida Book.