Sec. 6.  Verbal and Real Propositions.—­Another important division of propositions turns upon the relation of the predicate to the subject in respect of their connotations.  We saw, when discussing Relative Terms, that the connotation of one term often implies that of another; sometimes reciprocally, like ‘master’ and ‘slave’; or by inclusion, like species and genus; or by exclusion, like contraries and contradictories.  When terms so related appear as subject and predicate of the same proposition, the result is often tautology—­e.g., The master has authority over his slave; A horse is an animal; Red is not blue; British is not foreign.  Whoever knows the meaning of ‘master,’ ‘horse,’ ‘red,’ ‘British,’ learns nothing from these propositions.  Hence they are called Verbal propositions, as only expounding the sense of words, or as if they were propositions only by satisfying the forms of language, not by fulfilling the function of propositions in conveying a knowledge of facts.  They are also called ‘Analytic’ and ‘Explicative,’ when they separate and disengage the elements of the connotation of the subject.  Doubtless, such propositions may be useful to one who does not know the language; and Definitions, which are verbal propositions whose predicates analyse the whole connotations of their subjects, are indispensable instruments of science (see chap. xxii.).

Of course, hypothetical propositions may also be verbal, as If the soul be material it is extended; for ‘extension’ is connoted by ‘matter’; and, therefore, the corresponding disjunctive is verbal—­Either the soul is not material, or it is extended.  But a true divisional disjunctive can never be verbal (chap. xxi.  Sec. 4, rule 1).

On the other hand, when there is no such direct relation between subject and predicate that their connotations imply one another, but the predicate connotes something that cannot be learnt from the connotation of the subject, there is no longer tautology, but an enlargement of meaning—­e.g., Masters are degraded by their slaves; The horse is the noblest animal; Red is the favourite colour of the British army; If the soul is simple, it is indestructible.  Such propositions are called Real, Synthetic, or Ampliative, because they are propositions for which a mere understanding of their subjects would be no substitute, since the predicate adds a meaning of its own concerning matter of fact.

To any one who understands the language, a verbal proposition can never be an inference or conclusion from evidence; nor can a verbal proposition ever furnish grounds for an inference, except as to the meaning of words.  The subject of real and verbal propositions will inevitably recur in the chapters on Definition; but tautologies are such common blemishes in composition, and such frequent pitfalls in argument, that attention cannot be drawn to them too early or too often.

CHAPTER VI