In saying all this, I do not forget that the same doctrines, as held in different religions, may be and often are held very differently, as belonging to distinct wholes or _forms_, as they are called, and exposed to the influence and the bias of the teaching, perhaps false, with which they are associated. Thus, for instance, whatever be the resemblance between St. Augustine’s doctrine of Predestination and the tenet of Calvin upon it, the two really differ from each other _toto cœlo_ in significance and effect, in consequence of the place they hold in the systems in which they are respectively incorporated, just as shades and tints show so differently in a painting according to the masses of colour to which they are attached. But, in spite of this, a man may so hold the doctrine of personal election as a Calvinist, as to be able still to hold it as a Catholic. However, I have been speaking of certitudes which remain unimpaired, or rather confirmed, by a change of religion; on the contrary there are others, whether we call them certitudes or convictions, which perish in the change, as St. Paul’s conviction of the sufficiency of the Jewish Law came to an end on his becoming a Christian. Now how is such a series of facts to be reconciled with the doctrine which I have been enforcing? What conviction could be stronger than the faith of the Jews in the perpetuity of the Mosaic system? Those, then, it may be said, who abandoned Judaism for the Gospel, surely, in so doing, bore the most emphatic of testimonies to the defectibility of certitude. And, in like manner, a Mahometan may be so deeply convinced that Mahomet is the prophet of God, that it would be only by a quibble about the meaning of the word “certitude” that we could maintain, that, on his becoming a Catholic, he did not unequivocally prove that certitude is defectible. And it may be argued, perhaps, in the case of some members of the Church of England, that their faith in the validity of Anglican orders, and the invisibility of the Church’s unity, is so absolute, so deliberate, that their abandonment of it, did they become Catholics or sceptics, would be tantamount to the abandonment of a certitude.