Consequently, upon all this we are quite consistent in maintaining that all great teachers of whatever kind are vehicles of revelation, each in his proper sphere, and in accepting their verified conclusions as Divinely true; while we reject them the moment they transgress their limits, as thereby convicted of unsound thinking, and therefore deprived of the Divine assistance which was the secret of their previous success. And though such transgression may in many cases involve a minimum of moral error, there are abundant instances in the history of thought that it is not always so. Francis Bacon, and the penitent, pardoned Abelard are typical, in different degrees, of a countless multitude of lesser men. 'For our knowledge of first principles,' says S. Augustine, 'we have recourse to that inner truth that presides over the mind. And that indwelling teacher of the mind is Christ, the changeless virtue and eternal wisdom of God, to which every rational soul has recourse. But so much only is revealed to each as his own good or evil will enables him to receive[211].' 'Nor is it the fault of the Word,' adds S. Thomas, 'that all men do not attain to the knowledge of the truth, but some remain in darkness. It is the fault of men who do not turn to the Word and so cannot fully receive Him. Whence there is still more or less darkness remaining among men, in proportion to the lesser or greater degree in which they turn to the Word and receive Him. And so John, to preclude any thought of deficiency in the illuminating power of the Word, after saying "that life was the light of men," adds "the light shineth in darkness, and the darkness comprehended it not." The darkness is not because the Word does not shine, but because some do not receive the light of the Word; as while the light of the material sun is shining over the world, it is only dark to those whose eyes are closed or feeble[212].'