III. The question is not whether reason has any use in theology. For we confess that its use is manifold both for illustration (by making clear divine mysteries from human and earthly things); for comparison (by comparing old things with new, versions with their sources, opinions of doctors and decrees of councils with the rule of the divine word); for inference (by drawing conclusions); and for argumentation (by drawing forth reasons to support orthodoxy [orthodoxian] and overthrow heterodoxy [heterodoxian]). But the question is simply whether it bears the relation of a principle and rule in whose scale the greatest mysteries of religion should be weighed, so that nothing should be held which is not agreeable to it, which is not founded upon and cannot be elicited from reason. This we deny …
IV The question is not whether reason is the instrument by which or the medium through which we can be drawn to faith. For we acknowledge that reason can be both: the former indeed always and everywhere; the latter with regard to presupposed articles. Rather the question is whether it is the first principle from which the doctrines of faith are proved; or the foundation upon which they are built, so that we must hold to be false in things of faith what the natural light or human reason cannot comprehend. This we deny.
What is the Reformed view on reason? Is any emphasis on reason (and logic) "rationalism" which we ought to reject? To hear some of the charges against the whole idea of systematic theology today, one would think that rational thinking along the line of foundations (axioms) and syllogisms is unbiblical. But was that what the Reformed tradition historically taught?
The Reformed Orthodox used syllogisms, plenty of them. After all, Logic was important to them for the process of intellectually rigorous thinking. Even those who reject Aristotle for people like Ramus are merely attempting to substitute one system of thinking for another, not eradicating reasoning altogether. Who were those who reject reason? It was the mystics who rejected reason for the idea of an unmediated direct encounter of the soul with God, through the practice of spiritual disciplines. Such was found in Medieval and Tridentine Roman Catholicism, as well as major segments of Anabaptism, but they were not a hallmark of the best of the Reformed tradition.
The rise of rationalism with the Socinians was a threat to the Reformed Orthodox because they use reason to argue against the doctrines of the faith. But the Reformed Orthodox do not therefore throw out the baby with the bathwater. Turretin distinguishes between the instrumental use of reason and the foundational use of reason (1.VIII.7), ascribing the former to true Christian theology and the latter to the error of the rationalistic Socinians. Reason, which is probably better termed "logic" since "logic" describes the laws and processes of reasoning, is meant to be used as a tool, not to create new propositions from thin air (the foundational view). Rather, the propositions are Scripture, and reason merely infers from them to their consequences.
Does human sin and human depravity therefore means that any focus on reason as an instrument is a compromise of the doctrine of total depravity? Does it mean that one must argue for a "qualitative" difference between the truth known by God (ectypically) and what we can come to know as truth as revealed to us? Turretin would not have agreed with such arguments. Rather, this is what Turretin wrote:
VIII. The darkness of the human intellect does not hinder sound reason from judging of the truth of connections and so contradictions. We allow indeed that it cannot judge of the truth of propositions (as ignorant of it per se and which it must seek from the law and testimony). But it does not follow from this that it cannot judge of the contradiction of the expositions, opinions and interpretations which men give of these mysteries. [1.X.8]
'Sound reason' seems almost to be autonomous and unaffected by the Fall, but that is because it is not the human faculty of reason Turretin speaks of here, but rather the laws of logic, which are laws and not human faculties. The transcendent law of non-contradiction for example does not care whether the human seeking to utilize it is sinless or fallen, as long as it is used properly. The problem with our human minds that are affected by total depravity is not that the laws of reason have been altered, for these laws are outside of us, but rather that we are unable to properly use these laws correctly all the time. Just like Pharisaism distorts the revealed holy law of God, so rationalists distorts the laws of logic. Pharisaism and the Judaizers did not cause the holy law of God to be unholy, for the fault is with them not with the law! Likewsie, the many forms of rationalism are not manifestations that reason is totally corrupted and unfit for spiritual uses, but rather the fault lies with the users (Man) rather than the instrument of reason.
Thus, in the Clark-Van Til controversy, Turretin's position will be much closer to Clark's. Turretin is of course clearer in teaching that we cannot comprehend God, and the archetypal/ectypal distinction is clearly maintained, BUT on the main issue of the place of reason, he stands with Clark on the instrumental use of reason and the possibility of sound reason even in depraved minds (whether depraved Man wants to use sound reason is another question altogether).