Did man’s fall into sin only partially compromise his mind, ruin and warp it, or fully destroy it?
If the fall only partially compromised the mind of man, then it follows that one can reason to the Christian faith by merely laying out the “bare facts” and addressing any questions that serve as obstacles to one’s evangelistic prospect. If not, however, then he requires a supernatural work from God to cause him to think properly not only about moral and spiritual realities, but also about reality in general. But if the fall fully destroyed the mind of man, such that he cannot reason properly in any sense about reality in general, let alone about moral and spiritual realities, then does this not result in something like hypercalvinism, a full on rejection of the ordained means by which God has chosen to regenerate and save men (i.e. the preaching of the Law and the Gospel)?
Since we can’t deny that the fall affected the mind of man negatively (cf. Rom 1:18-32), and we can’t deny that the effects of the fall are not such that the preacher and apologist’s job to preach the Law and the Gospel to the unregenerate is one that is completely disconnected from how the elect will hear and respond to the Gospel. we are left with only one conclusion, namely –
The fall warped, and thereby ruined, the mind of man as regards his ability not only to reason about moral and spiritual realities, but also in his ability to reason about reality in general.
The mind of man is not simply bad at perceiving, reasoning about, believing, and living in accordance with moral and spiritual realities, but also fails to perceive, reasoning about, believing, and living in accordance with reality in general.
Mind & Conscience Are Both Ruined By The Fall
This is, in fact, what the Scriptures teach. Note, for instance, what Paul says in Titus 1:15 –
To the pure, all things are pure, but to the defiled and unbelieving, nothing is pure; but both their minds and their consciences are defiled.
In this one sentence, Paul the apostle makes it clear that the warping and ruining of man’s mind by the fall covers not merely man’s ability to correctly perceive, reason about, believe in, and live in accordance with moral and spiritual realities, but also his ability to do those things as they apply to reality in general.
Note how Paul differentiates between the “mind” and the “conscience” in this short passage. Seeing as the mind (Gr. νοῦς, nous) is the place where thinking about all subjects takes place, by stating that it and the conscience (Gr. συνείδησις, syneidēsis) are corrupted/defiled by sin, Paul is teaching that man’s mind in general is warped/corrupted/ruined by sin, i.e. as a consequence of being an unregenerate man. And if the mind in general is ruined/corrupted/defiled by sin, i.e. the fall, then it inexorably follows that the mind of man is so when engaged with any particular idea.
Paul’s differentiation between the mind in general and the conscience (i.e. the mind in a particular mode of operation, viz. moral and spiritual reasoning) seems to stress how the fall even more acutely affected the mind of man when it comes to spiritual and moral matters. Matthew Poole puts the matter simply –
…their mind, their notion and understanding, is defiled; and their conscience, which is the practical judgment they make up about things, is defiled…
Gill rightly comments on this passage, explaining that “there is nothing that defiled persons can do, but what is unclean; as are their persons, so are their offerings and works.” And since the injunction to give the glory to God covers all things (cf. 1st Cor 10:31), then it follows necessarily that those who are in the flesh cannot think in general in a way that glorifies God, for “those who are in the flesh cannot please God” (Rom 8:8).
You Must Be Born Again
If the mind of fallen man is warped in its basic functions, it follows that tools like debate, study, discourse, and friendship are only as effective as God causes them to be. Some may object to the idea that the mind of man is thoroughly warped, for, they would argue, this would seem to suggest that a man must believe in order to be able to believe, which would not only render preaching and teaching and doing apologetics unnecessary, it would also be self-contradictory. But this objection is based on that false assumption that if God commands men to do something (e.g. believe the Gospel) then man is able to do that thing (e.g. understand the Gospel and believe it). The reason why this assumption is false is simple – commands do not imply anything.
Logically, then, what one is commanded to do does not imply that the one receiving the command is capable of obeying it. What is more, Scripture teaches us that God commands men to do what they are incapable of doing. Jesus commanded the paralytic to get up and walk (cf. Mark 2:10-12), the man with a withered hand to stretch it out (cf. Mark 3:1-5), and a dead girl to rise from the dead (cf. Mark 5:-42). None of these people had the ability to do what they were commanded by God to do, yet he clearly commanded them to do the impossible. And perhaps most famously, he did the same in the case of Lazarus in John 11:43-44. In none of these cases did the command of Christ imply that his hearers were capable of obeying him – for (i.)commands do not imply anything, and (ii.)God clearly does command men to do what they are incapable of doing.
What is needed is a supernatural work in the heart of fallen man, the work of regeneration performed by the Holy Spirit wherein the sinner is brought to spiritual life, receiving the ability to reason in general correctly about himself and the world in which he exists, and, most importantly, receives the ability to reason correctly about moral and spiritual matters. The mind of man is only restored by this divine work of regeneration that results in the transformation of his nature and, consequently, the transformation of how he thinks about anything at all.
Apart from this, the minds of fallen men are corrupt in general, and even more corrupt as regards moral and spiritual realities.
Soli Deo Gloria