I say that it does not follow, because M. or N. happens to be a Protestant, that he is intellectually superior to Ampère, or because M. or N. happens to be a Unitarian, or a Deist, or a Positivist, that he is intellectually superior to Dr. Arnold or Sydney Smith. And on the other side of this question it is equally unfair to conclude that because a man does not share whatever may be our theological beliefs on the positive side, he must be less capable intellectually than we are. Two of the finest and most disciplined modern intellects, Comte and Sainte-Beuve, were neither Catholics, nor Protestants, nor Deists, but convinced atheists; yet Comte until the period of his decline, and Sainte-Beuve up to the very hour of his death, were quite in the highest rank of modern scientific and literary intellect. The inference from these facts which concerns every one of us is, that we are not to build up any edifice of intellectual self-satisfaction on the ground that in theological matters we believe or disbelieve this thing or that. If Ampère believed the doctrines of the Church of Rome, which to us seem so incredible, if Faraday remained throughout his brilliant intellectual career (certainly one of the most brilliant ever lived through by a human being) a sincere member of the obscure sect of the Sandemanians, we are not warranted in the conclusion that we are intellectually their betters because our theology is more novel, or more fashionable, or more in harmony with reason. Nor, on the other hand, does our orthodoxy prove anything in favor of our mental force and culture. Who, amongst the most orthodox writers, has a more forcible and cultivated intellect than Sainte-Beuve?--who can better give us the tone of perfect culture, with its love of justice, its thoroughness in preparation, its superiority to all crudeness and violence? Anglican or Romanist, dissenter or heretic, may be our master in the intellectual sphere, from which no sincere and capable laborer is excluded, either by his belief or by his unbelief. LETTER VI. TO A ROMAN CATHOLIC FRIEND WHO ACCUSED THE INTELLECTUAL CLASS OF A WANT OF REVERENCE FOR AUTHORITY. Necessity for treating affirmations as if they were doubtful--The Papal Infallibility--The Infallibility of the Sacred Scriptures--Opposition of method between Intellect and Faith--The perfection of the intellectual life requires intellectual methods--Inevitable action of the intellectual forces.