In the progress of life, though we are often gratified with the prospect of benevolence increasing as its objects increase, and of powers rising over the greatness of their past attainments, this gratification is not always ours. Not slight changes of character only appear, which require our attentive investigation to trace them, but, in innumerable cases, complete and striking contrasts press, of themselves, upon view. How many melancholy opportunities must every one have had in witnessing the progress of intellectual decay, and the coldness that steals upon the once benevolent heart! We quit our country, perhaps at an early period of life, and, after an absence of many years, we return with all the remembrances of past pleasure, which grow more tender as we approach their objects. We eagerly seek him, to whose paternal voice we have been accustomed to listen, with the same reverence as if its predictions had possessed oracular certainty,--who first led us into knowledge, and whose image has been constantly joined in our mind, with all that veneration which does not forbid love. We find him sunk, perhaps, in the imbecility of idiotism, unable to recognize us--ignorant alike of the past and of the future, and living only in the sensibility of animal gratification. We seek the favourite companion of our childhood, whose gentleness of heart we have often witnessed when we have wept together over the same ballad, or in the thousand little incidents that called forth our mutual compassion, in those years when compassion requires so little to call it forth. We find him hardened into man, meeting us scarcely with the cold hypocrisy of dissembled friendship--in his general relations to the world, careless of the misery which _he_ is not to feel--and, if he ever think of the happiness of others, seeking it as an instrument, not as an end. When we thus observe all that made us _one_, and gave an heroic interest even to our childish adventures, absorbed in the chillness of selfish enjoyment, do we truly recognize in him the same unaltered friend, from whom we were accustomed to regret our separation, and do we use only a metaphor of little meaning, when we say of him, that he is become a different person, and that his mind and character are changed? In what does the identity consist? The same objects no longer act upon him in the same manner; the same views of things are no longer followed by similar approbation or disapprobation, grief, joy, admiration, disgust; and if we affirm _that substance_ to be, in the strictest sense of identity, the _same_ on which, in two corresponding series of phenomena, the same objects act differently, while itself also acts differently on the same objects; in short, in which the antecedents being the same, the consequents are different, and, the consequents being the same, the antecedents are different, what definition of absolute diversity can we give, with which this