if that method
were employed in its fullest extent--if the same incapability of
believing otherwise could be shown as common to all mankind--it might
still be only the effect of a strong association. The analytical method
must still be called in to ascertain whether we are forced to suppose
such incapability to be an original fact of consciousness, or whether it
may not have been generated in the mind by circumstances under the
natural working of the laws of association. It is certain that these
laws not only may, but must, give birth to artificial inconceivabilities
in the mind--and that some of these may be equal in strength to such, if
any, as are natural.

'The History of Science' (says Mr Mill, following out the
same train of reasoning which we read in the third Book of
his 'System of Logic') 'teems with inconceivabilities which
have been conquered; and with supposed necessary truths,
which have first ceased to be thought necessary, then to be
thought true, and have finally come to be deemed
impossible.'--p. 150.

After various observations, chiefly exhibiting the rashness of many
censures bestowed by Sir W. Hamilton on Brown, Mr Mill gives us three
valuable chapters (xi., xii., xiii.), wherein he analyzes the belief in
an External World, the Belief in Mind as a separate substance or
Noumenon, and the Primary Qualities of Matter. To each of these topics
he applies what he calls the _psychological_ method, as contrasted with
the simply _introspective_ method of Sir W. Hamilton (the Ego and
Non-Ego affirmed to be given together in the primary deliverance of
Consciousness) and so many other philosophers. He proves that these
beliefs are no way intuitive, but acquired products; and that the known
laws of Association are sufficient to explain how they are acquired;
especially the Law of Inseparable Association, together with that of
_Obliviscence_--a very useful, discriminating phrase, which we first
find employed in this volume--(p. 259 et passim). He defines Matter to
be a _permanent possibility of Sensation_; he maintains that this is
really all which (apart from philosophical theories) mankind in general
mean by it; he shows that mere possibilities of sensation not only may,
but must, according to the known Laws of Association, come to present
'to our artificialized Consciousness' a character of objectivity--(pp.
198, 199). The correlative subject, though present in fact and
ind