The reason for his errors is highlighted by St Peter as follows:
2 Peter 1:7-9
"And in godliness, love of brotherhood; and in love of brotherhood, charity. For if these things be with you and abound, they will make you to be neither empty nor unfruitful in the knowledge of our Lord Jesus Christ. For he that hath not these things with him, is blind, and groping, having forgotten that he was purged from his old sins."
It matters not how great is one's natural intelligence, without the Holy Ghost we are blind to religious truth. If one falls away from God's commandments, then the Holy Ghost withdraws as we see in the allegory of Samson and the 7 gifts of the Holy Ghost:
Judges 16:19-21
"But she made him sleep upon her knees, and lay his head in her bosom. And she called a barber, and shaved his seven locks, and began to drive him away, and thrust him from her: for immediately his strength departed from him. And she said: The Philistines are upon thee, Samson. And awaking from sleep, he said in his mind: I will go out as I did before, and shake myself, not knowing that the Lord was departed from him.
Then the Philistines seized upon him, and forthwith pulled out his eyes, and led him bound in chains to Gaza, and shutting him up in prison made him grind.