statuentibus placet: non enim arte factorum ideas dari ajebant, sed natura procreatorum_). For the rest, the doctrine of Ideas originated with the Pythagoreans, unless we distrust the assertion of Plutarch in the book, _De placitis philosophorum_, L. i. c. 3. The individual is rooted in the species, and time in eternity. And as every individual is so only because it has the nature of its species in itself, so also it has only temporal existence because it is in eternity. In the following book a special chapter is devoted to the life of the species. In § 49 of the first volume I have sufficiently brought out the difference between the Idea and the conception. Their resemblance, on the other hand, rests upon the following ground: The original and essential unity of an Idea becomes broken up into the multiplicity of individual things through the perception of the knowing individual, which is subject to sensuous and cerebral conditions. But that unity is then restored through the reflection of the reason, yet only _in abstracto_, as a concept, _universale_, which indeed is equal to the Idea in extension, but has assumed quite a different _form_, and has thereby lost its perceptible nature, and with this its thorough determinateness. In this sense (but in no other) we might, in the language of the Scholastics, describe the Ideas as _universalia ante rem_, the conceptions as _universalia post rem_. Between the two stand the individual things, the knowledge of which is possessed also by the brutes. Without doubt the realism of the Scholastics arose from the confusion of the Platonic Ideas, to which, since they are also the species, an objective real being can certainly be attributed, with the mere concepts to which the Realists now wished to attribute such a being, and thereby called forth the victorious opposition of Nominalism. Chapter XXX.(10) On The Pure Subject Of Knowledge.