This isn't exactly correct. Man has the ability to understand and believe the gospel. But...he is disinclined to do so. He understands the gospel, but rejects it because to him it is foolishness.
His inability is in the area of inclination. Hence, the necessity of a new heart.
I think "inclination" is related to logic, and it seems more logical to me (after studying humanity’s variety of beliefs) given the existential facts of death and imperfect justice that
a person would have a propensity or inclination to hope the Christian view is correct, because there seems to be no better (credible and desirable) way of attaining the DOD (heaven and Justice) than NT theism. This Propensity Principle (PP) restates Pascal’s wager in terms of comparison shopping (with all belief systems) instead of gambling.
The PP employs linear logic (rather than circular reasoning) to propose faith in the NT God as the best belief that solves the maze of reality as follows:
1. Current scientific knowledge cannot explain how the universe came to exist by means of natural causes, thus it is possible that the cause of the universe is a supernatural Creator/God.
2. The most creative species is humanity, whose traits also include language, moral conscience and God consciousness (personality), so it is possible that these human traits reflect attributes of a God who created humanity.
3. Existential reality indicates that humans are mortal and life is painful, but when life is happy, one wishes it would continue indefinitely. Thus, it is rational to seek a way to become immortal in a heavenly existence (where there is love and justice for all forever, the DOD).
4. Comparing all possible ways of achieving the DOD, the best or most credible way/hope at this point appears to be the God who resurrected Christ Jesus according to the NT.
5. When words from God are sought, the NT teachings of Jesus and Paul seem to be the most highly inspired when compared with other scriptures (including the OT), because its concept of one God as the just and all-loving Judge (rationale for morality) is spiritually highest or most advanced, and the evidence for the resurrection of Jesus is most credible.
6. Thus, it is appropriate or wise to believe in the NT God and to accept Jesus as God’s Messiah, until/unless a better hope for heaven becomes available.
The atheist opinion or inclination is that the existence of a supernatural Deity is not proven, but it is not disproved either, which means that the evidence needs to be evaluated honestly.
A neutral inclination about ultimate reality is the following: “It is logical to remain open to believing all credible possibilities (those which present sufficient evidence) and to hope the most desirable rational possibility is true.” The PP explains why the NT is such.
A biblical illustration of the PP is the OT story about Naaman being told to bathe in the dirty Jordan River to cure his leprosy (2KG 5:10-14). The Naaman Example teaches us not to let sinful pride/inclinations prevent us from being cured of spiritual sickness by methods we think are silly or do not understand. Some people might not understand why God ordained Messiah to atone for humanity’s sins, so they think the Gospel seems foolish or silly (cf. 1CR 1:18-25). However, they accept physical reality without necessarily understanding very well how it works (cf. JN 3:8). God’s way: humility = teachability.
Those who reject the PP (and Naaman Example) apparently employ
a logical fallacy or inclination I call non praecedere (comparable to
non sequitur), making an unwarranted conclusion which precedes unknown facts, namely the cause for the universe “banging bigly”. Atheists assume a natural cause will be discovered, but their assumption is premature and thus inappropriate as well as nihilistic.