PHILOSOPHY, MENTAL. 
ral laws agreeable to which they are pro- 
duced, and then to employ those laws in 
the explanation of other phenomena. Men- 
tal philosophy pursues the same method 
which has been so successfully adopted in 
natural philosophy ; and as in physics simi- 
lar phenomena are referred to the operation 
of some one cause or power, so in mental 
science those phenomena which have all 
one common feature are referred to some 
faculty or property of the mind, by whose 
operation these phenomena are supposed to 
be produced. What those mental or phy- 
sical powers are, philosophy does not profess 
to explain. 
C. If we hold a luminous body before the 
eye it produces some change in the state of 
that organ, and this produces in the mind a 
feeling; this feeling is called a sensation. 
This name is also given to all those other 
feelings which are produced in a similar 
way, viz. owing to a change in the organs of 
sense, whatever be the cause by which the 
change is produced.— The general fact or 
law is, that sensations are produced by 
what affects the organs of sense. Now to 
account for this fact, we infer that the mind 
is possessed of a power or capacity which 
we call sensation, or, better to avoid am- 
biguity, the sensitive power. This then is 
that power or capacity of the mind by 
whose operation it receives sensations from 
things which affect the organs of sense. 
7. We know as a matter of fact, that 
though sensations cease soon after the ex, 
citing object is withdrawn, yet if they have 
been produced sufficiently often and vividly, 
the causes of feelings similar in kind remain 
in the mind, and those similar feelings can 
recur when no change is produced in the 
organs of sense. These are called ideas : 
they are the relicts of sensations. — Such is 
the general law or fact. The operation or 
act of retaining relicts of sensations, may 
with the strictest propriety be termed re- 
tention ; and to account for it, we infer that 
the mind possesses a power or capacity, 
which we may call the retentive power. 
This then is that power or capacity of the 
mind, by whichitretains relicts of sensations. 
8. Again ; it is an indisputable fact, that 
tliese ideas or relicts of sensations, do not 
remain single in the mind, but become con- 
nected with one another, so that the recur- 
rence of one, or of its corresponding sensa- 
tion, will bring on another ; and that in cer- 
tain cases they become so blended together, 
that the parts can scarcely be distinguished. 
Thus the word orange either pronounced or 
thought of, will bring tlie idea of the ap- 
pearance of an orange. Again, the idea of 
the word house is accompanied by a certain 
feeling which is altogether ditfeient from 
that which accompanies the idea of the 
word ship ; if we think about it a little, we 
usually have the idea of a particular house 
recalled ; this is a simple idea (_or idea of 
sensation or conception) connected with 
other ideas, but not combined with them : 
but, in general, if the word occurs without 
the mind dwelling upon it, we may perceive 
an indistinct feeling, which is composed of a 
variety of simple ideas, received from a 
variety of those objects to which we give 
the name house. That the feeling is thus 
composed we have a full right to assert, on 
an attentive consideration of the customary 
processes of the mind. — Simple ideas may 
then be connected with other ideas ; or 
they may blend and coalesce with other 
ideas, so as to form new ones, which are 
called compound or complex ideas. The 
general fact is, that conne.xions and compo- 
sitions take place among our ideas ; and 
when thus connected or compounded, we 
say that they are associated together, and 
the connected or compounded group W'e 
call an association. To account for the 
formation of associations, we infer that the 
mind possesses a power or capacity of con- 
necting or combining ideas, which may be 
called the associative power. This then is 
that power or capacity of the mind by 
which it connects and compounds ideas. 
9. Once more; it is obvious that without 
any external excitement of the nerves by 
which muscular motion is produced, the 
mind can produce such motion ; in other 
words, that state of the motory nerves by 
which muscular motion js effected, can be 
produced by the mind, We do not here 
inquire how the mind learns to use its influ- 
ence over the motory nerves, but state the 
tact, that muscular motion can be produced 
by the mind without external excitement. 
To account for this we infer that the mind 
possesses a power or capacity of influencing 
the motory nerves so as to produce muscu- 
lar motion, which may be called the motive 
power. — We have no name appropriate to 
those states of mind which produce the 
changes in the motory nerves requisite for 
muscular motion ; and we are therefore so 
far free from a difficulty which has accom- 
panied us when speakiilg of sensations and 
ideas : these terms, as they are generally 
used, imply that the consciousness of the 
mind is excited. But it appears an alpjost 
