either by our own science or the report of scientific men, we have obtained confidence in the use of an optical glass, we look no longer to it—but through it, and to the object on which object it is that our attention terminates and rests. And after that by the tuition of nature under which the homeliest peasant has risen to as great a proficiency as ourselves, we have acquired the confident use of our senses, we look neither to them nor to the mind, but from the mind and on the object of contemplation. 9. Although to the physiology of the mind belong all those powers and processes, by which it is that it acquires the knowledge of things which are separate from itself, and therefore the working of this physiology is anterior to the acquirement of all knowledge-yet the knowledge of this physiology is not so anterior. The physiology may be at work, soundly and successfully at work, without being at all understood or even adverted to—just as a man may operate rightly and fulfil the whole practical object of some piece of machinery that has been put into his hands, although he understands not the construction of it. The mental physiology in regard to its being must have the historical precedency over all science-but the science of this physiology has no such historical precedency over all other science. Suppose, that, instead of access by consciousness to the mechanism of my own intellect, I had access by some new channel of observation to the mechanism of the intellect of another man, and that I saw him busily and prosperously engaged in the study or contemplation of some one department of external nature -it is by looking to him certainly, that I should extend my knowledge of the world of spirit-but it would be by looking to the very same place on which his regards are fastened, that I should extend my knowledge of the world of sense. For this latter purpose, I would just as little look towards him, as he is doing himself, at the moment when his attention is intently fastened on some outer field of contemplation. To obtain the accurate perception of a tree, I should not look to the faint and perhaps muddy reflection of it, from the waters of that lake on whose margin it is standing and neither should I look to the mind of another, nor yet to my own mind, that from the mental reflection which is exhibited there, I might learn of that material world which stands in its own direct revelation before me. 10. It has been affirmed in plea for the priority of the study of mind over all other studies, that it is only by means of just conceptions in regard to the powers and the province of the human intellect, that certain illusions have been dissipated which were not merely unphilosophical in themselves, but which, so long as they lasted and had currency in the world, did effectually baffle the progress of all philosophy. But we, I contend, who now are in a state of freedom from these illusions, have no call upon us for attending to the process by which they were destroyed. The ingenious sophistries of Hume led to the conclusion that the material world had no existence but in our own shadowy imaginations. But is that a reason why, ere I enter on the Natural Philosophy by which the laws of matter are investigated, I who have no doubt upon the subject, must first be satisfied of the superior force of that reasoning by which the sophistries of Hume have been overthrown? I am not at all troubled with those sensible species which schoolmen chose to interpose between the human mind and those external realities by which it is encompassed—and am I therefore to be troubled ere I can clear my way to an immediate converse with these realities, with those masterly demonstrations of a sounder and better intellectual Philosophy, by which all the species and spectres of the middle ages have at length been put to flight? Because there are men in all ages, who have wandered from the direct path of simplicity and common sense in pursuit of some laborious follies of their own, can I who do not share in these follies only find access to that path across the still more laborious Philosophy which has now extinguished them for ever? The elaborate perversities of the human mind may require the elaboration equally severe of some great master-spirit to overturn them. But now that these perversities have gone into oblivion, and the temporary purpose of their utter destruction has been accomplishedis it for us to leave the obvious and rectilineal path which Nature has marked out, in pursuit of every wild deviation, or even of the retracing path by which the wanderers have been called back again. We utterly refuse the right of human folly in past generations to lay such a tax upon posterity-and though aware that a whole millennium of thickest intellectual darkness passed over the world, and that it was only dispersed by the philosophy of Bacon→→→ yet now that he has set us on the right path of investigation, in that path we may go, alike unconscious of those false lights by which our ancestors were bewildered, or of that greater light which put out them all. The confidence of Nature was disturbed by the reveries of the schoolmen. But now that these reveries are dissipated the confidence is restored. And without once having looked on the Novum Organum of Bacon, there is not a human creature in the maturity of his ordinary understanding, who does not know his great and simple lesson, and only great because of the monstrous absurdities by which for ages it was wholly overborne-even that to ascertain the visible qualities of an object we must look, or its sonorous qualities we must listen, or its tangible qualities we must handle, or its dimensions we must measure. * 11. There is no doubt that the view which we are led to take on every one subject of human knowledge is dependent on the physiology of the mind. But that is not to say that we must therefore become first acquainted with this physiology, ere we set ourselves to the acquirement of all other knowledge. There can be no doubt that because such is the constitution of the mind, such therefore *Dugald Stewart says in Vol. II. p. 36, 37 of his Philosophy of the Moral and Intellectual Powers" The science of abstruse learning, I consider in the same light with the ingenious writer, who compares it to Achilles' spear that healed the wounds that it made before. It serves to repair the damage itself had occasioned, and this perhaps is all it is good for. It casts no additional light upon the paths of life; but disperses the clouds with which it had overspread them before. It advances not the traveller one step on his journey, but conducts him back again to the spot from which he wandered. The are its modes of reasoning and of judging on all the objects of possible contemplation. But it does not on that account follow, that we must first study this constitution ere we proceed to the study of any thing else. The powers of the mind are antecedent to the acquirements of the mind. But the knowledge of those powers by which the acquirements are gotten is not antecedent to that knowledge in which the acquirements consist. mind is the instrument of all its own acquisitionsbut the instrument has been long tried and used and has also accomplished a great deal of work, before its properties have become the objects of our separate investigation. It is true that without a retina and without a picture of that which is external being spread out there, there could have been no science of optics. But it is just as true that it would have been as clear and demonstrative a science as it is at this moment, though anatomists had never found their way to this phenomenon, and the very first touch of their dissecting instrument had so injured the whole of the visual apparatus as to have made the exhibition impossible. And in like manner, there is a certainty and an evidence in many of the sciences that is altogether unaffected either by the success or the failure of our speculations on the mental physiology. When I look to the lines and the angles of Geometry, it is not to the diagram upon my retina, but to the diagram upon the paper or upon the board-and in like manner when I prosecute the train of its clear and resistless argumentations, I look only to the evidence that beams upon me from the subject itself, |