PHILOSOPHY, MENTAL. 



conscious or percipient principle is, is 

 probably known to him only who formed 

 it: we may believe consciousness orper- 

 cipiency to be a property which is the 

 necessary result of, or added to, a cer- 

 tain organized system of matter; or we 

 may believe it to be a property of some 

 substance essentially different from mat- 

 ter; and we apprehend it is not of much 

 consequence which opinion is adopted: 

 but it seems indisputable, that in the 

 present state of knowledge, we cannot 

 obtain, on either side, more than a bare 

 preponderance of probabilities. 



11. That organized substance, which, 

 without 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 motions or other changes, without 

 any further medium, consciousness is 

 excited, may be called the mental organs. 

 By the mind, w r e understand the whole 

 together, the conscious or percipient 

 principle together with the sensorium; 

 leaving it undecided, whether conscious- 

 ness is a property of organized matter, 

 or belongs to a substance essentially dif- 

 ferent from matter; and also, whether the 

 sensorium be or be not the medullary sub- 

 stance of the brain. (See SENSATION.) 

 Hartley, as is well known, adopts the 

 affirmative in the latter case; and he 

 supposes that the changes of the sensori- 

 um which affect the consciousness are 

 vibrations of the medullary substance 

 (see VIBRATION) ; we consider this hy- 

 pothesis as a clog upon, at least, the 

 adoption of his grand system of associa- 

 tion, and should prefer the more gene- 

 ral term, motions, if we professed to de- 

 cide respecting the nature of the senso- 

 rium ; as we do not, we shall employ the 

 still more general term changes, since 

 the term affections is already appropri- 

 ated. The changes in the sensorium, or 

 mental organs, which may excite the con- 

 sciousness, may be called sensorial chan- 

 ges. Of these some are produced by the 

 impression of external objects upon the 

 organs of sense; these may be called 

 sensible changes ; others, as we know by 

 their effects, are producible without the 

 presence of external objects; these may 

 be called ideal changes, and are the re- 

 licts of sensible changes; a third class 

 are those which are followed by muscu- 

 lar action, and may be termed motory 

 changes. Each of these classes of sen- 

 sorial changes may take place without 

 consciousness, as we shall endeavour to 



show in the next paragraph. When 

 sensible changes are accompan ; ed with 

 consciousness, they are called sensations; 

 when ideal changes are accompanied with 

 consciousness, they are called ideas; and 

 as sensible and ideal changes are princi- 

 pally important to us when accompanied 

 with consciousness, and it seldom is ne- 

 cessary to distinguish between those 

 which do and those which do not excite 

 it, we shall not usually depart from the 

 customary nomenclature. We have no 

 term appropriated to denote motory 

 changes accompanied with conscious- 

 ness: this deficiency probably arises from 

 the circumstance, that muscular action is 

 so much an object of the senses, that by 

 association it is referred to the moving 

 muscle, and not to the intermediate 

 fibrous motions and sensorial changes; 

 thus, while writing, all the motion seems 

 to be in the fingers, and in the fingers 

 alone, though even the minutest motion, 

 except that which is produced by some 

 external stimulus upon the motory nerve, 

 implies motory changes of the sensorium, 

 and should, scientifically speaking, be 

 referred to the sensorium, or mind. 



12. To show that sensible changes are 

 not necessarily accompanied with con- 

 sciousness, we observe, that the diminu- 

 tion of consciousness can be traced in 

 its various stages, from the state of active 

 attention, to cases where w T e have no rea- 

 son to believe that consciousness is ex- 

 cited, where yet we have abundant rea- 

 son to believe that there were sensible 

 changes ; because those effects are pro- 

 duced, which we know are produced by 

 sensations (that is, by sensible changes 

 of which we are conscious), and, as far 

 as we know, in no other way. We can- 

 not, consistently with our requisite limits, 

 advance so many facts as may appear to 

 some to be necessary to prove our state- 

 ments, but the following will at least 

 illustrate them. Persons, much accus- 

 tomed to employ notes in singing, some- 

 times feel so deeply interested in the 

 thoughts and feelings excited by the 

 words they are singing, that, though the 

 notes continue to regulate their tones of 

 voice, the sensible changes are altogether 

 unnoticed by them; they do not excite 

 the consciousness. Again, many who 

 have been long accustomed to perform 

 upon a musical instrument, and can play 

 with ease at first sight, while playing a 

 piece of music which they have not seen, 

 before, can converse and carry on a train 

 of reasoning, and yet play correctly : the 

 appropriate sensible changes must in 



