There are many great thinkers within the Church. There are many great thinkers who wandered down wrong paths based on their thinking.
Cardinal Newman seems to have managed the former without falling into the latter. Not that he "found the truth" and became Catholic, but that he thought deeply by letting the truth guide him. What I mean by that is that he submitted himself to the truth without protest or struggle. The truth was an objective thing to which he could only defer within his own thought. This led him to a clarity and simplicity of thought about the truth.
How often do we want to mold others or the truth to our own thought! Such is not the path of those who trust the truth but those who wish to make the truth. Such is not the path of love but of sin. We must move ourselves out of the way so that God may illuminate the mind. May we let John guide us to emulate him in humble submission to the truth so that the truth may truly set us and everyone we come into contact with, free.
But let us, finding ourselves in the state in which we are, take those means which alone are really left us, which alone become us. Adam, when he had sinned, and felt himself fallen, instead of honestly abandoning what he had become, would fain have hid himself. He went a step further. He did not give up what he now was, partly from dread of God, partly from dislike of what he had been. He had learnt to love sin and to fear God's justice. But Christ has purchased for us what we lost in Adam, our garment of innocence. He has bid us and enabled us to become as little children; He has purchased for us the grace of simplicity, which, though one of the highest, is very little thought about, is very little sought after. We have, indeed, a general idea what love is, and hope, and faith, and truth, and purity, though a poor idea; but we are almost blind to what is one of the first elements of Christian perfection, that simple-mindedness which springs from the heart's being whole with God, entire, undivided. And those who think they have an idea of it, commonly rise no higher than to mistake for it a mere weakness and softness of mind, which is but its counterfeit. To be simple is to be like the Apostles and first Christians.
-- From Sermon 18, Ignorance of Evil
Things to Think About