the laws of my
nature_) could unmake it; but _I_ (i.e. _my will_) cannot. In the
Free-Will controversy, 'I' is used ambiguously for volitions, actions,
and mental dispositions, and 'Necessity' both for _Certainty_ and for
_Compulsion_. From the application of 'same,' 'one,' 'identical,' which
primarily refer to a single object, to several objects because
_similar_, grew up (for the purpose of accounting for the supposed
_oneness_ in things said to have the _same_ nature or qualities) both
the Platonic _Ideas_, and also the _Substantial Forms_ and _Second
Substances_ of the Aristotelians, even though the latter did see the
distinction between things differing both _specie_ and _numero_, and
those differing _numero_ only. And thence, too, sprang Berkeley's proof
of the existence of a Universal Mind from the supposed need of such a
Being to harbour, in the interval, the idea, which, one and the same
(really, only two _similar_ ideas), a man's mind has entertained at two
distinct times. The difficulty in _Achilles and the Tortoise_ arises
from the use of _infinity_, or, _for ever_, in the premisses, to
signify a finite time which is infinitely divisible, and, in the
conclusion, to signify an infinite time. Thus, again, 'right' is used to
express, both what others have no right to stop a man from doing, and
also what it is not against his own duty to do; both what people are
entitled to expect from, and also what they may enforce from others. The
Fallacy of Composition and Division, i.e. the use of the same term in a
syllogism, at one time in a collective, at another in a distributive
sense, is one of the Fallacies of Ambiguous Terms. Examples of it are
the arguments, that _great men_ (collectively) could be dispensed with,
because the place of any particular great man might have been supplied
(i.e., in fact, by some other great man); and, that a high prize in a
lottery may be reasonably expected (by _a certain individual_, viz.
oneself), because a high prize is commonly gained (_by some one or
other_).

2. In Petitio Principii, the premisses are not even verbally sufficient
for the conclusion, since one premiss is either clearly the same as the
conclusion, or actually proved from it, or not susceptible of any other
proof. Men commonly fall into it, through believing that the premiss
_was_ verified, though they have forgotten how. But the variety, termed
Reasoning in a Circle, implies a conscious attempt to prove two
propos