235The sceptical philosophy, already advocated in the Middle Ages by John of Salisbury, was, like every other form of ancient thought, revived at the Renaissance, but only under419 the very superficial form which infers from the co-existence of many divergent opinions that none of them can be true. Even so, however, it led Montaigne to sounder notions of toleration and humanity than were entertained by any of his contemporaries. With Bacon, and still more with Descartes, it also appears as the necessary preparation for a remodelling of all belief; but the great dogmatic systems still exercised such a potent influence on both those thinkers that their professed demand for a new method merely leads up to an altered statement of the old unproved assumptions.