The man who hears Christ’s words and yet builds his life on a rejection of that revelation is a fool (Matt. 7:26), and the man who suppresses God’s general revelation in the created realm is also described as a fool (Rom. 1:18).
It is quite clear, then, that a fool is one who does not make God and His revelation the starting point (the presupposition) of his thinking. Fools despise the preaching of the cross, refuse to know God, and cannot receive God’s word (1 Cor. 1-2).
The self-proclaimed autonomous man, the unbeliever, will not submit to the word of God or build his life and thinking upon it. Disbelief and ignorance of God’s will, therefore, produce foolishness (1 Cor. 15:36; Eph. 5:17).
Bahnsen, Greg. "Always Ready". Kindle Locations 361-367 (ch 13).