The professed point of difference stated in the same Letter—namely, that the Thomists and Sorbonnists (and of course the Port Royalists with them) held that efficacious grace is resistible, while Calvin held that it was irresistible—may or may not hold in reference to special expressions of Calvin. But there is nothing, upon the whole, stronger in Calvin than there is in Augustine on the subject of grace; and on the other hand, an “efficacious grace,” which is “resistible”—which the human heart can accept or repel _at will_—seems open to all the ironical play which Pascal directs so skilfully in his first Letters against the Jesuit doctrine of a _sufficient_ grace which is not yet sufficient. The truth is, that apart from verbal subtleties, which Pascal could handle no less familiarly, only far more skilfully, than his adversaries, there is no rational position intermediate between the Pelagian doctrine (which is also substantially the Aristotelian) of free will and moral habit, and the Augustinian doctrine of Divine grace and spiritual inspiration. The source of character is either from within the character itself, which has power to choose good and to be good if it will, or it is from a higher source—the grace of God, and the power of a Divine ordination. These are the only real lines of controversy. The Christian thinker may decline controversy on such a subject altogether, acknowledging that the mystery of character is in its roots beyond our ken,—that we know not, and in the nature of the case cannot know, where the Human ends and the Divine begins. In such a case there is no room for argument. But we cannot with consistency step off one line on to the other. In other words, we cannot logically abuse Calvin while we hold with Augustine, or profess to revere St Thomas while we abuse Jansen. But it is more than time to turn from this side of the ‘Provincial Letters.’ This was the controversy out of which they sprang—which mingles itself most with the personality of Pascal—and hence it has claimed a somewhat detailed treatment. The great subject to which the intervening and chief portion of the Letters is directed is not, indeed, more important in itself, but it is more diversified, and more practically interesting. Here, however, Pascal was more obviously performing a task than in the other Letters. He was speaking less out of his heart. Having grappled with the Jesuits, and noticed their tactics in the affair of the Sorbonne, he is led to look into their whole system. He takes up their books and studies them, in part at least; while his friends Nicole and Arnauld also study them for him. And the result is the remarkable and memorable assault contained in his thirteen Letters—from the fourth to the sixteenth—directed against all the main principles of the Jesuit system.