The occasion of all their difficulty originated in an attempt to nvestigate the faculties of the mind without any means of getting at it. They did not content themselves with an adoption of the principles which lay at the foundation of all true philosophy, viz., that the facts to be accounted for, do exist; that truth is eternal, and we are to become acquainted with it by the means employed for its development.

They quitted the world of materiality they inhabited, refused to examine the development of mind as the effect of an existing cause; and at one bold push, entered the world of thought, and made the unhallowed attempt to reason, a priori, concerning things which can only be known by their manifestations. But they soon found themselves in a strange land, confused with sights and sounds unknown, in the explanation of which they, of course, choose terms as unintelligible to their readers, as the ideal realities were to them. This course, adopted by Aristotle, has been too closely followed by those who have come after him.[2] But a new era has dawned upon the philosophy of the mind, and a corresponding change in the method of inculcating the principles of language must follow.[3]

In all our investigations we must take things as we find them, and account for them as far as we can. It would be a thankless task to attempt a change of principles in any thing. That would be an encroachment of the Creator's rights. It belongs to mortals to use the things they have as not abusing them; and to Deity to regulate the laws by which those things are governed. And that man is the wisest, the truest philosopher, and brightest Christian, who acquaints himself with those laws as they do exist in the regulation of matter and mind, in the promotion of physical and moral enjoyment, and endeavors to conform to them in all his thoughts and actions.

From this apparent digression you will at once discover our object. We must not endeavor to change the principles of language, but to understand and explain them; to ascertain, as far as possible, the actions of the mind in obtaining ideas, and the use of language in expressing them. We may not be able to make our sentiments understood; but if they are not, the fault will originate in no obscurity in the facts themselves, but in our inability either to understand them or the words employed in their expression. Having been in the habit of using words with either no meaning or a wrong one, it may be difficult to comprehend the subject of which they treat. A man may have a quantity of sulphur, charcoal, and nitre, but it is not until he learns their properties and combinations that he can make gunpowder. Let us then adopt a careful and independent course of reasoning, resolved to meddle with nothing we do not understand, and to use no words until we know their meaning.

A complex idea is a combination of several simple ones, as a tree is made up of roots, a trunk, branches, twigs, and leaves. And these again may be divided into the wood, the bark, the sap, &c. Or we may employ the botanical terms, and enumerate its external and internal parts and qualities; the whole anatomy and physiology, as well as variety and history of trees of that species, and show its characteristic distinctions; for the mind receives a different impression on looking at a maple, a birch, a poplar, a tamarisk, a sycamore, or hemlock. In this way complex ideas are formed, distinct in their parts, but blended in a common whole; and, in conformity with the law regulating language, words, sounds or signs, are employed to express the complex whole, or each distinctive part. The same may be said of all things of like character. But this idea I will illustrate more at large before the close of this lecture.

First impressions are produced by a view of material things, as we have already seen; and the notion of action is obtained from a knowledge of the changes these things undergo. The idea of quality and definition is produced by contrast and comparison. Children soon learn the difference between a sweet apple and a sour one, a white rose and a red one, a hard seat and a soft one, harmonious sounds and those that are discordant, a pleasant smell and one that is disagreeable. As the mind advances, the application is varied, and they speak of a sweet rose, changing from taste and sight to smell, of a sweet song, of a hard apple, &c.

According to the qualities thus learned, you may talk to them intelligibly of the sweetness of an apple, the color of a rose, the hardness of iron, the harmony of sounds, the smell or scent of things which possess that quality. As these agree or disagree with their comfort, they will call them good or bad, and speak of the qualities of goodness and badness, as if possessed by the thing itself.