that of the perception of such objects. As such exclusively, it is to be explained, and not as something different from a real perception of something external. This is what philosophy is bound to do, if she speaks at all. Now what is the explication given by the theories under consideration? The perception of an object external to the mind, is explained by a profound demonstration, that no such object, nor perception of such object, exists in the Intelligence, and that such perception is an inexplicable impossibility. Now this is not the explanation of a fact, but its destruction, the most unphilosophical procedure-a procedure very much like the Frenchman's definition of the flea, to wit, an animal upon which, if you put your finger, he is not under it.

4. These theories involve an explication equally sophistical and unphilosophical of the question, in respect to the certainty and reality of knowledge. An apprehension of an object exists in the Intelligence. Philosophy is called upon to answer the question, whether this apprehension is valid, in respect to the object? If it is so, our knowledge is real, certain. What answer do these theories give to this question? This. Our knowledge is certain and absolute, for the obvious reason, that the object has no existence at all; that the perception itself is the only thing real, and as it contains nothing but what the Intelligence has put into it, therefore our knowledge is real and absolute. What a strange answer this to the question, the only question submitted to philosophy, to wit, the validity of the perception. relatively to its object.

5. These theories annihilate wholly all distinctions between truth and error, all criteria of truth whatever. The reality, the certainty of knowledge, according to these theories, consists in this-that as our conceptions are the only realities existing, and as these contain nothing but what the Intelligence puts into them, therefore our knowledge is real, is absolute. Now, this condition of certainty holds, in respect to one conception, just as well as another; and if this is the condition of certainty, the wildest vagaries of the maniac are just as true as the sublimest demonstrations of Newton.

6. Finally, all such theories give a totally false explication of the real procedure of the Intelligence in respect to knowledge of every kind. Let any one attempt to apply such theories, as elucidating the process of his own mind in

its perceptions and knowledges, and the effect cannot be better expressed, than in the following extract of a letter written to Coleridge by a friend, explaining to the philosopher the effect of a careful study of his theory of the Imagination:

"As to myself, and stating, in the first place, the effect on my understanding, your opinions and method of argument were not only so new to me, but so directly the reverse of all I had ever been accustomed to consider as truth, that, even if I had comprehended your premises sufficiently to have admitted them, and had seen the necessity of your conclusions, I should still have been in that state of mind, which, in your note, p. 251, you have so ingeniously evolved, as the antithesis to that in which a man is when he makes a bull. In your own words, I should have felt as if I had been standing on my head.

"The effect on my feelings, on the other hand, I cannot better represent, than by supposing myself to have known only our light, airy, modern chapels of ease, and then, for the first time, to have been placed, and left alone, in one of our largest Gothic cathedrals, in a gusty moonlight night of autumn. Now in glimmer, now in gloom;' often in palpable darkness, not without a chilling sensation of terror; then suddenly emerging into broad, yet visionary light, with colored shadows of fantastic shapes, yet all decked with holy insignia and holy symbols; and, ever and anon, coming out full upon pictures, and stone-work images, and great men, with whose names I was familiar, but which looked upon me with countenances, and an expression, the most dissimilar to all I had been in the habit of connecting with those names. Those whom I had been taught to venerate as almost superhunian in magnitude of intellect, I found perched in little fret-work niches, as grotesque dwarfs; while the grotesques, in my hitherto belief, stood guarding the high altar with all the characters of apotheosis. In short, what I had supposed substances, were thinned away into shadows, while, everywhere, shadows were deepened into substances:

'If substance may be call'd what shadow seem'd,
For each seem'd either!'"

Now, a theory which gives such an explanation of the process of the human Intelligence as this, does not give a true exposition of that process. There is surely no presumption in such an affirmation as this.

In the remarks above made upon the theories under consideration, I have anticipated some things which properly belong to a later department of mental science; no more, however, than was necessary to a distinct presentation of our present subject of investigation.

DISTINCTION OF QUALITIES AS PRIMARY AND SECONDARY.

A few remarks upon the distinction commonly made with regard to the qualities of material substances, will close this Chapter. These qualities are distinguished as primary and secondary. The former are such as are essential to the substance as material, such, for example, as solidity and extension. The latter are not essential to the existence of the substance as matter, such, for example, as color, temperature, taste, and smell. Our knowledge of the former is direct; of the latter, it is only indirect and relative. perties of external things we know such things, says Mr. Stewart, only "as the unknown cause of a known sensation." On these distinctions, I would simply present the following suggestions:

As pro

1. I would raise a query, whether color is properly ranked as a secondary quality? Can we conceive of a material substance which is, to any being, an object of vision (and every such substance may be to some being, such an object), and is yet destitute of color? For myself, I find it impossible to form such a conception of such a substance.

The principal argument which I present in favor of this position, however, is the fact, that all men believe it, even philosophers, in the very act of an attempted demonstration of the opposite opinion. "We know well," says Dr. Brown (a strange assertion, that we know well, what he goes on to show we cannot believe even while attempting to prove it), "when we open our eyes, that whatever affects our eyes is within the small compass of their orbit; and yet we cannot look for a single moment, without spreading what we thus visually feel over whole miles of landscape. Still, I must repeat, not the slightest doubt is philosophically entertained by those, who, when they open their eyes, yield like the vulgar to the temporary illusion-that the colors, thus supposed to be spread over the external objects, or rather the rays of light that come from them, are merely the unknown causes of certain sensations in ourselves. When questioned on the subject of vision, we state this opinion with

confidence, and even with astonishment, that our opinion. on the subject, in the present age of philosophy, should be doubted by him who has taken the superfluous trouble of putting such a question. At the very moment, probably, at which we give our answer, we have our eyes fixed on him to whom we address it. His complexion, his dress, are regarded by us as external colors, and we are practically, at the very moment, therefore, belying the very opinion which we profess, and in speculation truly profess, to hold."

For myself, my opinions must undergo an essential modification before I shall hold a dogma philosophically, which I cannot but disbelieve, even in the act of attempting to demonstrate its truth. A philosopher once asked a friend, why the atmosphere above us appears blue? The friend attempted to account for the fact, by reference to the laws of reflection of light. The philosopher replied, that he had a much more simple, and to himself a much more satisfactory answer: The sky appears blue, because it is blue." The answer indicated an insight into the depths of philosophic wisdom. It is the very answer which true philosophy gives to all similar questions.

2. Our vision of objects is direct and immediate, and not indirect and mediate. The presence of light, the image on the retina, the consequent effect upon the Sensibility, through the optic nerve, are conditions of vision, but no part of vision itself. When these conditions are fulfilled, we see, not what is within the small compass of the orbs of vision, but the objects themselves towards which those orbs are turned. I hold the truth of this theory, for the reason that it announces, as the real and necessary belief of the race, what philosophy is bound to do, the real belief of philosophers, when in the very act of attempted demonstrations of the opposite theory. Let any man attempt to write a demonstration of the theory, that we never, in reality, see objects without us, and in the act of writing that demonstration, he will believe that he has a direct vision of the paper on which he is writing out an attempted demonstration of the position, that he has no such vision. Now, a theory which I cannot believe, even when attempting to demonstrate its truth, I shall never consent to receive as philosophically true. Philosophy will announce much fewer errors than it now does, when it will cease to enunciate as philosophically true, what all men, and philosophers with them, know to be intellectually false.

3. Nor is it true, as some suppose, that primary qualities exist in the objects themselves, while the secondary qualities exist only in the Sensibility which experiences them. There is nothing in the external object, it is said, like the sensation of color, taste, or smell. Nor is there anything in the object like the sensation of resistance. As causes of specific sensations, secondary qualities sustain precisely the same relation to their appropriate effects that primary qualities do. The only ground for the distinction under consideration, is this: we cannot conceive of a material substance which is not solid and extended; but we may conceive of one which is destitute of taste, smell, &c.

Secondary qualities are also just as essential to the peculiar nature of the substances in which they inhere, as the primary ones. We cannot take away a primary quality, without so changing the nature of its subject, that it will no longer be material. Nor can we take away a secondary quality (the quality in sugar, for example, which produces in us the sensation of sweetness), without changing its nature, as that particular thing.

Nor is our knowledge of the nature of substances less real and positive, through the secondary, than through the primary qualities of matter. My knowledge of the real nature of sugar, for example, through the sensation of sweetness, is just as real as is my knowledge of any other substance, through the perception of form, or the sensation of resistance. All that I know, in either instance, is the real correlation between the nature of Mind and Matter, through perceptions and sensations.