Click on the phrases to see them in context. The original texts by Immanuel Kant and David Hume are available from the Gutenberg Projet.

Now, as in the merely speculative employment of reason the latter is properly the sole aim, and as in this case the approximation to a conception, which is never attained in practice, is the same thing as if the conception were non-existent--it is commonly said of the conception of this kind, "it is only an idea." So we might very well say, "the absolute totality of all phenomena is only an idea," for, as we never can present an adequate representation of it, it remains for us a problem incapable of solution.