Our differences are founded in this very thought. Protestants believe the Holy Spirit speaks directly to individual believers through Scripture and prayer. To read the Bible is to know this for a fact.
We're instructed to worship God as a congregation of believers, to study Scripture together and rightly divide the word of God, but we are never to doubt the Holy Spirit is leading our study.
It's true that some men think they are being led when they are not. But that does not negate the absolute fact that some men, by the grace and will of God alone, are being led in righteousness to all truth.
For ye have not received the spirit of bondage again to fear; but ye have received the Spirit of adoption, whereby we cry, Abba, Father. The Spirit itself beareth witness with our spirit, that we are the children of God: And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together." -- Romans 8:14-17"For as many as are led by the Spirit of God, they are the sons of God.
Our job is to read the Scriptures and...
"Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth." -- 2 Timothy 2:15
And in doing so, we will "prove what is that good, and acceptable, and perfect, will of God" (Romans 12:2).
I must admit I chuckled a bit because soooo many times (especially on the science threads) I've had occasion to testify as to the "proof" of God which is of course not a scientific proof (since God cannot be put under a microscope or observed with a telescope) --- but one which in no way can be mistaken.
That proof of course is the indwelling Spirit Himself. I have known Him personally - and Jesus Christ, personally, because of Him - for nigh onto a half century and counting.
An atheist's claim that God doesn't exist is a knee-slapper to a Christian.
No, I think that's why the Holy Spirit speaks to the individual through the Word, prayer and believing friends so there won't be the arrogant nonsense of group think.
Jesus said, "Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them."
When the Episcopal church ordained a practicing homosexual, Vickie Gene Robinson, the people participating said they were being led by the Holy Spirit. This is obviously patently untrue as they were defying God's word in Holy Scripture. Many other Protestant denominations are also ordaining homosexuals, encouraging their parishioners to practice birth control, and approving abortion and divorce. The Catholic church's stance for God's Law and for the Gospel of Life are two of the many reasons I converted from being a Protestant (first Presbyterian then Episcopal).
There are 30,000 different Protestant denominations now and the number is growing. This is contrary to Jesus' wishes for us. We can know this by reading the High Priestly Prayer found in John 17 where Jesus prays 5 times that "they all may be one" (vs. 11, vs. 21 [twice], vs. 22, vs. 23). St. Ignatius of Antioch, who was martyred at Rome between 90-117 AD and was probably a friend of St. John the Apostle said this in his letter to the Philadelphians 3.2: "Do not err, my brethren. If any man follows him that makes a schism in the Church, he shall not inherit the kingdom of God. If any one walks according to a strange opinion, he agrees not with the passion of Christ." This man knew the Apostles and those who followed the Apostles and knew what their teaching was, which they had been taught by Jesus. The teaching of Jesus, the Apostles, and the Early Church Fathers is that there be ONE CHURCH.
I will not question that last statement. I believe it to be true. But I believe that the vast majority of men have so much spiritual static and have so much of their own egos and personal lusts in the way that the Spirit doesn't get through. I have been to many Bible studies both Catholic and non-Catholic; and I've talked with well-meaning non Catholics and it is very obvious that many of them are not being led by the Spirit to their conclusions.
I have had the unfortunate experience of having had a distant relative committed to mental hospital in my home town. While visiting her, I have had the privilege of meeting Jesus Christ (probably a dozen of them), John the Baptist (twice), Napolean, Washington, Jefferson, Lincoln and either Marilyn Monroe or Jayne Mansfield. The little voices told them, too.
How can one show that it is the Spirit moving through them, and not demonic voices or internal whims? Even Satan can quote Scripture for his own ends. Answer: the One Holy Catholic and Apostolic Church - the one that Jesus Christ founded. Jesus did not leave Scripture. He left His Church that the gates of Hell will not prevail against.
I do not intend to say that all non Catholics are driven by the Devil; rather that the Devil delights in the creation of multiple churches rather than the One Church and in the private interpretation of Scripture rather than the One Church's teachings. That way, the message is garbled, people can be subtly misled and therefore trapped eternally in Hell. After all, the road to Hell is paved with good intentions.