produce-rents,
ground-rents, customary rents, and so forth, (Cf. Dr. Keynes' _Scope
and Method of Political Economy_, chap. 5.)

Sec. 6. Definitions affect the cogency of arguments in many ways, whether
we use popular or scientific language. If the definitions of our terms
are vague, or are badly abstracted from the facts denoted, all arguments
involving these terms are inconclusive. There can be no confidence in
reasoning with such terms; since, if vague, there is nothing to protect
us from ambiguity; or, if their meaning has been badly abstracted, we
may be led into absurdity--as if 'impudence' should be defined in such a
way as to confound it with honesty.

Again, it is by definitions that we can best distinguish between Verbal
and Real Propositions. Whether a term predicated is implied in the
definition of the subject, or adds something to its meaning, deserves
our constant attention. We often persuade ourselves that statements are
profound and important, when, in fact, they are mere verbal
propositions. "It is just to give every man his due"; "the greater good
ought to be preferred to the less"; such dicta sound well--indeed, too
well! For 'a man's due' means nothing else than what it is just to give
him; and 'the greater good' may mean the one that ought to be preferred:
these, therefore, are Truisms. The investigation of a definition may be
a very valuable service to thought; but, once found, there is no merit
in repeating it. To put forward verbal or analytic propositions, or
truisms, as information (except, of course, in explaining terms to the
uninstructed), shows that we are not thinking what we say; for else we
must become aware of our own emptiness. Every step forward in knowledge
is expressed in a real or synthetic proposition; and it is only by means
of such propositions that information can be given (except as to the
meaning of words) or that an argument or train of reasoning can make any
progress.

Opposed to a truism is a Contradiction in Terms; that is, the denying of
a subject something which it connotes (or which belongs to its
definition), or the affirming of it something whose absence it connotes
(or which is excluded by its definition). A verbal proposition is
necessarily true, because it is tautologous; a contradiction in terms is
necessarily false, because it is inconsistent. Yet, as a rhetorical
artifice, or figure, it may be effective: that 'the slave is not bound
to obey his master' may