But when Paul perceived that one part were Sadducees and the other Pharisees, he cried out in the council, "Men and brethren, I am a Pharisee, the son of a Pharisee; concerning the hope and resurrection of the dead I am being judged!" And when he had said this, a dissension arose between the Pharisees and the Sadducees; and the assembly was divided. For Sadducees say that there is no resurrection - and no angel or spirit; but the Pharisees confess both. (Acts 23:6-8)
We find many people in Scripture who passed themselves off as being deeply religious intellectuals, but were not saved. This was the condition of the Jewish Pharisees and Sadducees who opposed Christ and the apostles, particularly Paul.
They represent large numbers of unbelievers in every generation in many respects. They were well-educated intellectuals who were blinded by their sin from believing the Gospel of Jesus Christ. Their unbelief was prejudiced opposition. They opposed the message of Christ because it contradicted their preconcieved but un-Biblical notions of God and of the Savior whom He would send. Many, like the Sadducees, denied the supernatural. Many people in every generation reject the Gospel for many of the same reasons. They think it is backward, old fashioned, and intellectually ridiculous.
But humanity's problems with Christianity are never simply intellectual or moral; at the core of unbelief lies opposition to God and His law. All are dead in trespasses and sin and unable to evaluate the truths of Christianity as merely rational thinkers. They are bound by their sinful nature in opposition to the message. This why the Gospel is of necessity a supernatural message supernaturally received. Without the regenerating power of the Holy Spirit, no one would be able to believe and be saved.