Recommended edition: Edited by W. P. D. Wightman and J. C. Bryce, vol. III of the Glasgow Edition of the Works and Correspondence of Adam Smith (Indianapolis: Liberty Fund, 1982).

Excerpt:

“Plato, however, seems to have regarded the first of those as equally distinct with the second from what we would now call the Ideas or Thoughts of the Divine Mind , and even to have supposed, that they had a particular place of existence, beyond the sphere of the visible corporeal world; though this has been much controverted, both by the later Platonists, and by some very judicious modern critics, who have followed the interpretation of the later Platonists, as what did most honour to the judgment of that renowned philosopher. All the objects in this world, continued he, are particular and individual. Here, therefore, the human mind has no opportunity of seeing any Species, or Universal Nature. Whatever ideas it has, therefore, of such beings, for it plainly has them, it must derive from the memory of what it has seen, in some former period of its existence, when it had an opportunity of visiting the place or Sphere of Universals. For some time after it is immersed in the body, during its infancy, its childhood, and a great part of its youth, the violence of those passions which it derives from the body, and which are all directed to the particular and individual objects of this world, hinder it from turning its attention to those Universal Natures, with which it had been conversant in the world from whence it came. The Ideas, of these, therefore, seem, in this first period of its existence here, to be overwhelmed in the confusion of those turbulent emotions, and to be almost entirely wiped out of its remembrance. During the continuance of this state, it is incapable of Reasoning, Science and Philosophy, which are conversant about Universals. Its whole attention is turned towards particular objects, concerning which, being directed by no general notions, it forms many vain and false opinions, and is filled with error, perplexity, and confusion. But, when age has abated the violence of its passions, and composed the confusion of its thoughts, it then becomes more capable of reflection, and of turning its attention to those almost forgotten ideas of things with which it had been conversant in the former state of its existence. All the particular objects in this sensible world, being formed after the eternal exemplars in that intellectual world, awaken, upon account of their resemblance, insensibly, and by slow degrees, the almost obliterated ideas of these last. The beauty, which is shared in different degrees among terrestrial objects, revives the same idea of that Universal Nature of beauty which exists in the intellectual world: particular acts of justice, of the universal nature of justice; particular reasonings, and particular sciences, of the universal nature of science, and reasoning; particular roundnesses, of the universal nature of roundness; particular squares, of the universal nature of squareness. Thus science, which is conversant about Universals, is derived from memory; and to instruct any person concerning the general nature of any subject, is no more than to awaken in him the remembrance of what he formerly knew about it. This both Plato and Socrates imagined they could still further confirm, by the fallacious experiment, which shewed, that a person might be led to discover himself, without any information, any general truth, of which he was before ignorant, merely by being asked a number of properly arranged and connected questions concerning it.”

Online:
Library of Economics and Liberty