Gordon Clark and his followers believe and proclaim the affirmative. They assert that the human intellect remained in its pristine condition even after man's descent into sin and that the sin problem is one solely of an ethical nature.
While the sin problem is indeed ethical, an immediate observation is the undue and coerced bifurcation made between reason and the will (an assumed independence). What the position seems to be saying is that the will can act independently of what the mind deems as good and fitting. Even in the case of addictions, where it seems that the will and emotions are acting in rebellion against the mind, the intellectual involvement is ever present in its estimation of the pleasure to be derived from engaging in the illicit act.
But what does one of the prime exponents of Reformed Orthodoxy have to say about the state of reason in unregenerate man? Let us reckon with Francis Turretin's words:
"(1) The reason of an unregenerate man is blinded with respect to the law (Eph. 4:17, 18; Rom. 1:27, 28; 8:7). With respect to the gospel, it is evidently blind and mere darkness (Eph. 5:8; 1 Cor. 2:14). Therefore, it must be taken captive that it may be subjected to faith, not exalted that it may rule it (2 Cor. 10:3-5*). (2) The mysteries of faith are beyond the sphere of reason to which the unregenerate man cannot rise; and, as the senses do not attempt to judge of those things which are out of their sphere, so neither does reason in those things which are above it and supernatural. (3) Faith is not referred ultimately to reason, so that I ought to believe because I so understand and comprehend; but to the word because God so speaks in the Scriptures. (4) The Holy Spirit directs us to the word alone (Dt. 4:1; Is. 8:20; Jn. 5:39; 2 Tim. 3:15, 16; 2 Pet. 1:19). (5) If reason is the principle of faith, then first it would follow that all religion is natural and demonstrable by natural reason and natural light. Thus nature and grace, natural and supernatural revelation would be confounded. Second, it would follow that reason is nowhere to be made captive and to be denied, against the express passages of Scripture, and that those possessed of a more ready mind and a more cultivated genius can better perceive and judge the mysteries of faith against universal experience (1 Cor. 1:19, 20; Mt. 11:25). (6) Reason cannot be the rule of religion; neither as corrupted because it is not only below faith, but also opposed to it (Rom. 8:7; 1 Cor. 2:14; Mt. 16:17); nor as sound because this is not found in corrupt man, nor in an uncontaminated man could it be the rule of supernatural mysteries. Nor now when it is corrected by the Spirit must it be judged according to itself, but according to the first principle which illuminated reason now admits (viz., the Scriptures)" (Institutes, I.1.8.5).
What could be clearer from a Reformed Orthodox standpoint?
Further, Turretin says:
"Although things of faith agree with reason and doctrine can be at variance with sound enlightened reason, it does not follow that they agree with corrupted and blind reason, or that even sound reason is its principle" (ibid., 19).
Corruption and blindness applied to the unregenerate's faculty of reason! Doesn't seem to line up with Clark's notion of uninterrupted intellectual bliss.
Also, the following statement might rub those who've elevated logic (translated: Clarkians) beyond its Scriptural warrant wrong:
"The proper rule of things to be believed and disbelieved is not the apprehension of their possibility or impossibility, but the word of God. Nor are those things only possible to God which seem so to men, for he can do above all that we can think (Eph. 3:20; Mt. 19:260, and it would be impious for a finite mind to circumscribe within narrow limits the infinite power of God" (ibid., 20).
Talk about a slap in the face of the Law of Noncontradiction!
If only Gordon Clark had interacted more with Reformed Orthodoxy. It's a good thing that that is precisely what Cornelius Van Til did, and we are better off for it.