Page:Ferrier's Works Volume 1 - Institutes of Metaphysic (1875 ed.).djvu/67

Rh, must philosophy in consistency with her own canon, convict natural thinking of being contradictory, but her procedure would be arrogant and irrational in the extreme, unless she were able to pronounce this sentence, doing so under the authority of the necessary Reason itself. Each deliverance, then, of ordinary thinking contradicts some necessary law or truth of all reason. This is shown, not by any roundabout argument, but by directly confronting the natural opinions of man with the necessary truths or laws which they contradict. This consideration determines the following arrangement The necessary truths or laws of all reason are laid down in a series of distinct propositions; and facing each of these propositions is laid down in a counter-proposition, the contradictory inadvertency of ordinary opinion, so that we can always play them off against each other, and know exactly what we are dealing with, what we are contending for, and what we are contending against. It will always be found that the psychological doctrine on any particular point coincides, either wholly or partially (generally wholly, or very nearly so), with the contradictory inadvertency of ordinary thought, and therefore the counter-propositions will be seen to represent faithfully the erroneous teachings of psychology, as well as the inadvertent decisions of common opinion. Proposition and counter-proposition are the two hinges of the system.