Page:A biographical dictionary of eminent Scotsmen, vol 5.djvu/46

106 not connected with anything which the mind had experienced,) had formed the outline of a similar division of knowledge; but neither of them founded on such a distinction, a system of philosophy, nor were they, it may be well conceived, aware of the extent to which the principles they suggested might be logically carried. The division we have endeavoured to define, is the foundation of the sceptical philosophy. The knowledge immediately derived from impressions is that which truly admits the term "knowledge" to be strictly applied to it; that which is founded on experience, derived from previous impressions, is something which always admits of doubt. While the former are always certain, the mind being unable to conceive their uncertainty, the latter may not only be conceived to be false, but are so much the mere subjects of probability, that there are distinctions in the force which the mind attributes to them sometimes admitting them to be doubtful, and making no more distinction, except in the greater amount of probabilities betwixt that which it pronounces doubtful, and that which it pronounces certain. As an instance—when a man looks upon another man, and hears him speak, he receives through the senses of hearing and sight, certain impressions, the existence of which he cannot doubt; on that man, however, being no longer the object of his senses, the impressions are arranged in his mind in a reflex form, constituting what Mr Hume has called ideas; and although he may at first be convinced in a manner sufficiently strong for all practical purposes, that he has actually seen and heard such a man, the knowledge he has is only a mass of probabilities, which not only admit him to conceive it a possibility that he may not have met such a man, but actually decay by degrees, so as probably after a considerable period to lapse into uncertainty, while no better line of distinction can be drawn betwixt the certainty and the uncertainty, than that the one is produced by a greater mass of probabilities than the other. The author would have been inconsistent, had he admitted the reception of knowledge of an external world, even through the medium of the senses: he maintained all that the mind had really cognizance of, to be the perceptions themselves; there was no method of ascertaining with certainly what caused them. The human mind, then, is thus discovered to be nothing but a series of perceptions, of which some sets have such a resemblance to each other, that we always naturally arrange them together in our thoughts. Our consciousness of the identity of any given individual, is merely a series of perceptions so similar, that the mind glides along them without observation. A man's consciousness of his own identity, is a similar series of impressions. "The mind," says the author, "is a kind of theatre, where several perceptions successively make their appearance—pass, repass, glide away, and mingle in an infinite variety of postures and situations. There is properly no simplicity in it at one time, nor identity in different, whatever natural propension we may have to imagine that simplicity and identity. The comparison of the theatre must not mislead us. They are the successive perceptions only that constitute the mind; nor have we the most distant notion of the place where these scenes are represented, or of the materials of which it is composed." From such a conclusion, the passage to scepticism on the immateriality of the soul was a natural and easy step: but on such a subject we must be cautious as to the manner in which we make remarks on the observations made by Hume—we neither appear as among his vindicators, nor for the purpose of disputing his conclusions—our purpose is, as faithful biographers, to give, as far as our limits and our knowledge of the subject may admit, a sketch of his leading doctrines; and if we have any thing to vindicate, it will be the author's real meaning, which certain zealous defenders of Christianity have shown an anxiety to turn as batteries against it. In his reasonings on the immateriality of the soul he is truly scepti-