But whilst the narrowness of human knowledge may well preclude all self-exaltation, it would be worse than folly to hold as naught the many important truths which have been wrought out for us by the mighty intellects of the past. If they have left us nothing for vainglory, they have left us at least enough to be grateful for. Nor is it a little, that they have taught us to look into those mysterious chambers of our being,--the abode of the spirit; and not a little, indeed, if what we are there permitted to know shall have brought with it the conviction, that we are not abandoned to a blind empiricism, to waste life in guesses, and to guess at last that we have all our lives been guessing wrong,--but, unapproachable though it be to the subordinate Understanding, that we have still within us an abiding Interpreter, which cannot be gainsaid, which makes our duty to God and man clear as the light, which ever guards the fountain of all true pleasures, nay, which holds in subjection the last high gift of the Creator, that imaginative faculty whereby his exalted creature, made in his image, might mould at will, from his most marvellous world, yet unborn forms, even forms of beauty, grandeur, and majesty, having all of truth but his own divine prerogative,--_the mystery of Life_. As the greater part of those Pleasures which we propose to discuss are intimately connected with the material world, it may be well, perhaps, to assign some reason for the epithet _mental_. To many, we know, this will seem superfluous; but, when it is remembered how often we hear of this and that object delighting the eye, or of certain sounds charming the ear, it may not be amiss to show that such expressions have really no meaning except as metaphors. When the senses, as the medium of communication, have conveyed to the mind either the sounds or images, their function ceases. So also with respect to the objects: their end is attained, at least as to us, when the sounds or images are thus transmitted, which, so far as they are concerned, must for ever remain the same within as without the mind. For, where the ultimate end is not in mere bodily sensation, neither the senses nor the objects possess, of themselves, any productive power; of the product that follows, the _tertium aliquid_, whether the pleasure we feel be in a beautiful animal or in according sounds, neither the one nor the other is really the cause, but simply the _occasion_. It is clear, then, that the effect realized supposes of necessity another agent, which must therefore exist only in the mind. But of this hereafter.