Here the term cannot be applied to our acts of perceiving, for no one would think of affirming our acts of perceiving to be like or unlike the objects perceived; nor can it be applied to the objects perceived, for that would be pronouncing the said objects to be like or unlike themselves. What, then, is the phrase "perception" here intended to designate? It is not the act, it cannot be the object. Where, then, are we to look for the tertium quid which is to give to the proposition the reality or even the semblance of a meaning? Or how is it that such a comparison has ever been made, and such a resemblance or non-resemblance predicated?

In a subsequent Letter I shall find a fitting place for an attempt to solve the problem, leaving it in the mean time as an exercise for your metaphysical sagacity.

The acceptation of the word before us becomes still more unsteady with those philosophers who speak of faculties and powers. It is apt in their writings to have a triple meaning, in some places denoting the faculty of perception, in others the act of perceiving, and in others the objects perceived. And in addition to these acceptations I may mention the very objectionable practice of some writers (Hume for instance) who speak of perceptions when they mean conceptions or ideas*, naturally, to be sure, on their theories.

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Nothing can ever be present to the mind but an image or perception."-Academical or Sceptical Philosophy.

This remark leads me to notice that with the word conception there is not the same liability to error from ambiguity as with the word perception; or, to express myself more precisely, while the latter may be used, as just mentioned, in three senses, the former can be used only in two.

In a passage which I quoted in a former Letter, Dugald Stewart furnishes an instance in point. "The business of conception," he remarks, "is to present us with an exact transcript of what we have felt or perceived," meaning of course that it is the business of the faculty so called.

He adds: "But we have, moreover, a power of modifying our conceptions, by combining the parts of different ones together, so as to form new wholes of our own creation;" in which passage he manifestly intends to designate, not the faculty itself, but the transcripts which, according to him, it is the business of the faculty to present.

Thus we may speak of the faculty of conception, and of the products or acts of that faculty -conceptions; but there is not, as in the case of perception, a separate object which can be confounded with the act under one name. We do, indeed, speak of the objects conceived or recollected; but it is manifest that these objects, not being actually in presence, bear to the act of conceiving them a very different relation from that which objects actually perceived bear to the act of perception.

In strictness there is implied in the term conception nothing but the act itself; there must, indeed, have been previously an object discerned, but at the actual moment there is none: it is then, in itself, an absolute unconnected state of mind.

From this it follows that, although in the use of perceptions for objects perceived, we must be on our guard against confounding acts and objects in our inferences, against ascribing to one what is true only of the other, yet a similar caution is not required with the word conceptions, the employment of which can lead to no such confusion. As, nevertheless, when conception is not used to designate a faculty, it is equivalent to idea, and interchangeable with it, I consider the latter term, in virtue of its not being applicable to either faculty or object, to be preferable to the former, and shall accordingly make a freer use of it in the sequel; for, notwithstanding the loose and indeterminate manner in which it has been frequently employed, I think it may be easily limited to a perfectly definite acceptation.

There are other names designating operations of the mind, such as recollection, judgment, belief, cognition, to which some of the preceding remarks, mutatis mutandis, are applicable; but I need not trouble you with bringing them into consideration at present they may possibly rise to the surface hereafter.

LETTER XIII.

THEORIES OF PERCEPTION.

IN glancing over my Table of mental operations and affections, you will perceive that there is ample room for comment and disquisition, besides the explanations I have already offered.

Agreeably, nevertheless, to what I said in my introductory Letter, that it was not my purpose to construct a system embracing an investigation of all the phenomena of mind, but to limit myself as much as possible to such of them as I thought I could elucidate by new considerations, or by putting old facts and arguments into a more definite and forcible shape,-I shall select for discussion, in the sequel, what may be regarded as the principal questions connected with the operations of perceiving and conceiving, without, however, excluding other topics that may incidentally arise.

Lest this should appear a rather narrow field to range in, I would call your attention to the fact, that I have in former works already treated at some length the important processes of believing and reasoning, and if I were to introduce them

here I should be only repeating what I have before advanced.

I may also remark, that the parts of mental philosophy which I have selected for particular consideration in the Letters which are to follow, embrace some of the profoundest problems that have ever been discussed.

After this preamble I proceed to the business before me.

It is singular, and at first sight unaccountable, how it should ever have been propounded, that in the act of perception, as, for example, in looking at a tree, there is an independent image, form, or phantasm, or idea of the tree interposed between the tree itself and the percipient being.

A man has only to look at any object before him, not contenting himself with words, to be satisfied of the non-existence of any such image or idea. To one of untutored and unperverted mind the very suggestion of such a thing would appear absurd. He perceives the external object, and, let him look as intently as he may, he can perceive nothing else.

Philosophers, however, were not content with simple facts, and a simple statement of these facts.

Amongst other conceits, divers of them appear to have entertained a notion that some such intervenient image or phantasm is requisite for the unmeaning reason, that the immaterial mind cannot come into contact with matter, or have any