Note 318 — Chapter I

It may be added that it is in this form that the cogency of the argument is most easily to be recognised. Of course every affirmation involves a denial and vice versâ ; but it may fairly be said that in Jevons’s example the primary force of the minor premiss, considered in connexion with the major premiss, is to affirm that carbon belongs to the class of non-metallic substances, rather than to deny that it belongs to the class of metallic substances.