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, in this intuition the thinking self must seek the conditions of the employment of its logical functions as categories of substance, cause, and so forth; not merely for the purpose of distinguishing itself as an object in itself by means of the representation "I," but also for the purpose of determining the mode of its existence, that is, of cognizing itself as noumenon.