PHILOSOPHY, MENTAL. 
indisputable fact, that the mental organs, 
whatever they be, by whose action the con- 
sciousness is excited, often are in a state of 
activity without sucli excitement of the 
consciousness; in other words, that those 
changes which wlien accompanied witli con- 
sciousness are termed sensations and ideas, 
may take place, and produce their appro- 
priate effect in the mental system, without 
exciting the conscious or percipient princi- 
ple. In order to enter into the consideration 
of this important fact, it will be necessary 
to consider somewhat more explicitly in 
what manner we employ the term mind, and 
to introduce some less customary terms in 
order to avoid ambiguity. 
10. In the philosophical sense of the 
term mind, it seems to belong exclusively 
to the conscious or percipient principle 
whatever that be ; but in common language 
we certainly emplby it differently : e. g.rio 
one hesitates in sajing, “ such a man has 
an extensive store of knowledge in his 
mind but no one supposes that at any one 
time a man perceives, that is, is conscious 
of, all the parts of that knowledge : in the 
same manner po one would hesitate in 
saying, “ such a person has a great fund of 
valuable reflections for the conduct of life 
stored up in his mind, which he can produce 
whenever circumstances call for them;” but 
no one supposes that those reflections are 
always in the view of his mind, that is, that 
he is always conscious of them, that he al- 
ways perceives them. All that can be 
meant in such cases is, that the causes of his 
ideas (that is of his thoughts and feelings) 
remain in the mind ready for excitement 
when they produce ideas. — Hence then the 
mind, in the common acceptation of the 
term, in which we use it, consists of two 
parts, the conscious or percipient principle, 
and the organized substance, which furnishes 
to the former the objects of its conscious- 
ness or percipiency. What the conscious 
or percipient principle is, is probably known 
to him only who formed it : we may believe 
consciousness or percipiency to be a pro- 
perty which is the necessary result otj or 
added to, a certain organized system of 
matter ; or we may believe it to be a pro- 
perty of some substance essentially different 
from matter ; and we apprehend it is not of 
much consequence which opinion is adopt- 
ed : but it seems indisputable, that in the 
present state of knowledge, we cannot ob- 
tain, on either side, more than a bare pre- 
ponderance of probabilities. 
^ 11 .That prganiged substance, which, with. 
out any further medium, furnishes to the 
conscious or percipient principle the objects 
of consciousness or percipiency, may be 
called the sensorium. The parts of which 
the sensorium is composed, by whose mo- 
tions or other changes, without any further 
medium, consciousness is excited, may be 
called the mental organs. By the mind, we 
understand the whole together, tlie consci- 
ous or percipient principle together with tlie 
sensorium ; leaving it undecided, w'hether 
consciousness is a property of organized 
matter, or belongs to a substance essentially 
different from matter, and also, whether 
the sensorium be or be not the medullary 
substance of the brain. (See Sensation.) 
Hartley, as is well known, adopts the affir- 
mative in the latter case ; and he supposes 
that the changes of the sensorium which af- 
fect the consciousness are vibrations of the 
medullary substance (see Vibration) ; we 
consider this hypothesis as a clog upon, at 
least, the adoption of his grand system of as- 
sociation, and should prefer the more gene, 
ral term, motions, if we professed to decide 
respecting the nature of the sensorium ; as 
we do not, we shall employ the still more 
general term changes, since the term affec- 
tions is already appropriated. — The changes 
in the sensorium, or mental organs, whicli 
may excite the consciousness, may be 
called sensorial changes. Of these some 
are produced by the impression of external 
objects upon the organs of sense ; thgse 
may be called sensible changes : others, as 
we know by their efiects, are producible 
without the presence of external objects ; 
these may be called ideal changes, and are 
the relicts of sensible changes ; a third class 
are tliose which are followed by muscular 
action, and may be termed raotory changes. 
Each of these classes of sensorial changes 
may take place without consciousness, as 
we shall endeavour to show in the next pa- 
ragraph. When sensible changes are ac- 
companied with consciousness, they are 
called sensations ; when ideal changes are 
accompanied with consciousness, they are 
called ideas; and as sensible and ideal 
changes are principally important to us 
when accompanied with consciousness, and 
it seldom is necessary to distinguish between 
those which do and those which do not ex- 
cite it, we shqll not usually depart from the 
customary nomenclature. We have no term 
appropriated to denote motory changes ac- 
companied with consciousness; tliis defi- 
ciency probably arises from the circum- 
stance, that muscular action is so much aq 
