Essays / by Adam Smith.

  • Smith, Adam, 1723-1790.
Date:
1869
Catalogue details

Licence: Public Domain Mark

Credit: Essays / by Adam Smith. Source: Wellcome Collection.

    403/482 (page 397)
    been describing, were, however, apprehended to go before it, in the order in which the knowledge of Nature ought to be communicated. The first of these. Metaphysics, considered the general nature of Uni- versals, and the different sorts or species into which they might be divided. The second of these. Logics, was built upon this doctrine of Metaphysics ; and from the general nature of Universals, and of the sorts into which they were divided, endeavoured to ascertain the general rules by which we might distribute all particular objects into general classes, and determine to what class each individual object be- longed ; for in this, they justly enough apprehended, consisted the whole art of philosophical reasoning. As the first of these two sciences, Metaphysics, is altogether subordinate to the second. Logic, they seem, before the time of Aristotle, to have been regarded as one, and to have made up between them that ancient Dialectic of which we hear so much, and of which we understand so little : neither does this separa- tion seem to have been much attended to, either by his own followers, the ancient Peripatetics, or by any other of the old sects of philoso- phers. The later schoolmen, indeed, have distinguished between Ontology and Logic ; but their Ontology contains but a small part of what is the subject of the metaphysical books of Aristotle, the greater part of which, the doctrines of Universals, and everything that is preparatory to the arts of defining and dividing, has, since the days of Porphery, been inserted into their Logic. According to Plato and Timteus, the principles out of which the Deity formed the World, and which were themselves eternal, were three in number. The Subject-matter of things, the Species, or Speci- fic Essences of things, and what was made out of these, the sensible objects themselves. These last had no proper or durable existence, but were in perpetual flux and succession. For as Heraclitus had said that no man ever passed the same river twice, because the water which he had passed over once was gone before he could pass over it a second time ; so, in the same manner, no man ever saw, or heard, or touched the same sensible object twice. When 1 look at the window, for example, the visible species, which strikes my eyes this moment, though resembling, is different from that which stmck my eyes the immediately preceding moment. When 1 ring the bell, the sound, or audible species, which I hear this moment, though re- sembling in the same manner, is different, however, from that which I heard the moment before. When I lay my hand on the table, the tangible species which I feel this moment, though resembling, in the same manner, is numerically different too from that which I felt the moment before. Our sensations, therefore, never properly exist or endure one moment; but, in the very instant of their generation, perish and are annihilated for ever. Nor are the causes of those sen- sations more permanent. No corporeal substance is ever exactly the