traitors the vilest of mankind?_ anticipates the answer, _Yes_. So
that the logical form of these sentences is, _Hypocrites are not lovers
of virtue_; _Traitors are the vilest of mankind_. Impersonal
propositions, such as _It rains_, are easily rendered into logical forms
of equivalent meaning, thus: _Rain is falling_; or (if that be
tautology), _The clouds are raining_. Exclamations may seem capricious,
but are often part of the argument. _Shade of Chatham!_ usually means
_Chatham, being aware of our present foreign policy, is much
disgusted_. It is in fact, an appeal to authority, without the
inconvenience of stating what exactly it is that the authority declares.

Sec. 2. But even sentences indicative may not be expressed in the way most
convenient to logicians. _Salt dissolves in water_ is a plain enough
statement; but the logician prefers to have it thus: _Salt is soluble in
water_. For he says that a proposition is analysable into three
elements: (1) a Subject (as _Salt_) about which something is asserted or
denied; (2) a Predicate (as _soluble in water_) which is asserted or
denied of the Subject, and (3) the Copula (_is_ or _are_, or _is not_ or
_are not_), the sign of relation between the Subject and Predicate. The
Subject and Predicate are called the Terms of the proposition: and the
Copula may be called the sign of predication, using the verb 'to
predicate' indefinitely for either 'to affirm' or 'to deny.' Thus _S is
P_ means that the term _P_ is given as related in some way to the term
_S_. We may, therefore, further define a Proposition as 'a sentence in
which one term is predicated of another.'

In such a proposition as _Salt dissolves_, the copula (_is_) is
contained in the predicate, and, besides the subject, only one element
is exhibited: it is therefore said to be _secundi adjacentis_. When all
three parts are exhibited, as in _Salt is soluble_, the proposition is
said to be _tertii adjacentis_.

For the ordinary purposes of Logic, in predicating attributes of a thing
or class of things, the copula _is_, or _is not_, sufficiently
represents the relation of subject and predicate; but when it is
desirable to realise fully the nature of the relation involved, it may
be better to use a more explicit form. Instead of saying
_Salt--is--soluble_, we may say _Solubility--coinheres with--the nature
of salt_, or _The putting of salt in water--is a cause of--its
dissolving_: thus expanding the copula into a ful