S o THE POPULAR SCIENCE MONTHLY. 



And the inevitable reaction of words upon thought has in this case 

 become so complete, and has penetrated so deeply, that when an accu- 

 rate statement of the case namely, that muskiness, inasmuch as the 

 term denotes nothing but a sensation, is a mental state and has no 

 existence except as a mental phenomenon is first brought under the 

 notice of common-sense folks, it is usually regarded by them as what 

 they are pleased to call a mere metaphysical paradox and a patent ex- 

 ample of useless subtilty. Yet the slightest reflection must suffice to con- 

 vince any one possessed of sound reasoning faculties that it is as absurd 

 to suppose that muskiness is a quality inherent in one plant, as it would 

 be to imagine that pain is a quality inherent in another, because we 

 feel pain when a thorn pricks the finger. 



Even the common-sense philosopher, par excellence, says of smell : 

 " It appears to be a simple and original affection or feeling of the mind, 

 altogether inexplicable and unaccountable. It is, indeed, impossible 

 that it can be in any body : it is a sensation, and a sensation can only 

 be in a sentient thing." * 



That which is true of muskiness is true of every other odor. Lav- 

 ender-smell, clove-smell, garlic-smell, are, like "muskiness," names of 

 states of consciousness, and have no existence except as such. But, in 

 ordinary language, we speak of all these odors as if they were indepen- 

 dent entities residing in lavender, cloves, and garlic ; and it is not 

 without a certain struggle that the false metaphysic of common sense, 

 thus ingrained in us, is expelled. 



It is unnecessary for the present purpose to inquire into the origin 

 of our belief in external bodies, or into that of the notion of causation. 

 Assuming the existence of an external world, there is no difficulty in 

 obtaining experimental proof that, as a general rule, olfactory sensa- 

 tions are caused by odorous bodies; and we may pass on to the next 

 step of the inquiry namely, how the odorous body produces the effect 

 attributed to it. 



The first point to be noted here is another fact revealed by experi- 

 ence ; that the appearance of the sensation is governed, not only by 

 the presence of the odorous substance, but by the condition of a certain 

 part of our corporeal structure, the nose. If the nostrils are closed, the 

 presence of the odorous substance does not give rise to the sensation ; 

 while, when they are open, the sensation is intensified by the approxi- 

 mation of the odorous substance to them, and by snuffing up the adja- 

 cent air in such a manner as to draw it into the nose. On the other 



* " An Inquiry into the Human Mind on the Principles of Common Sense, chap, ii., 

 sec. 2. Reid affirms that " it is genius and not the want of it that adulterates philosophy, 

 and fills it with error and false theory " ; and no doubt his own lucubrations are free 

 from the smallest taint of the impurity to which he objects. But, for want of something 

 more than that " common sense," which is very common and a little dull, the contemner 

 of genius did not notice that the admission here made knocks so big a hole in the bottom 

 of " common-sense philosophy " that nothing can save it from foundering in the dreaded 

 abyss of Idealism. 



