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

The proposition, "I think," is, in the present case, understood in a problematical sense, not in so far as it contains a perception of an existence (like the Cartesian "Cogito, ergo sum"),[Footnote; "I think, therefore I am."] but in regard to its mere possibility--for the purpose of discovering what properties may be inferred from so simple a proposition and predicated of the subject of it.