trusted to with entire confidence, wherever they afford us clear and distinct ideas of their respective objects.

In the second place, it will undoubtedly be admitted that the sensations, which have been spoken of, have an existence. This existence, it is true, is wholly internal ; but still the simple fact remains that they exist; our consciousness most decisively teaches us so. But it has been laid down as a primary truth, a first principle, that there is no beginning or change of existence without a cause. This is an elementary principle, placed as far above all objection and scepticism as any one can be, and evidently preliminary to the full exercise of reasoning.

And where then is the cause of these internal effects? What man, who denies the existence of the material world, is able to indicate the origin of these results? If, yielding to the suggestions of our nature and the requisitions of our belief, we seek for a cause external to ourselves, we find a satisfactory explanation; otherwise we may expect to find none of any kind.

§. 95. The senses as much grounds of belief as other parts of our con

stitution.

FURTHERMORE, it must be admitted, as has already been particularly stated and shown, that there are certain original sources or grounds of belief in our constitution. To say otherwise would be to loosen and destroy the foundations of all knowledge, whether that knowledge has relation to matter or mind. But what evidence is there, that there are such original sources of belief, or that any one thing in particular is the foundation of such belief more than any other thing? The answer is, our own internal consciousness and conviction, and this merely; we are conscious of belief, and are able to trace it to the occasions which give it rise.

Now if we carefully examine our minds, we shall find, that the intimations from the senses as effectually cause belief, as any other source of evidence whatever. Our consciousness, our internal conviction tells us, that our belief is as decisively regulated by the perceptions, derived through the senses, as by our intuitive or inductive perception; and that they are as much a ground of knowledge. We assert

this with confidence; therefore, if the senses are not a ground of belief and knowledge, the way is fairly open for unlimited scepticism on all subjects. It will in this case be impossible to fix upon any thing whatever, which is to be received as evidence, and men must give up all knowledge of intellect as well as matter, and will be at once released from all moral obligation.

§. 96. Opinions of Locke on the testimony of the senses.

As the satisfactory understanding of this subject is of much practical importance, we shall close what has been said upon it by some passages from Mr. Locke.-"If after all this, (he says in the Fourth Book of his Essay,) any one will be so skeptical as to distrust his senses, and to affirm that all we see and hear, feel and taste, think and do, during our whole being, is but the series and deluding appearances of a long dream, whereof there is no reality; and therefore will question the existence of all things, or our knowledge of any thing; I must desire him to consider, that, if all be a dream, then he doth but dream that he makes the question; and so it is not much matter that a waking man should answer him. But yet, if he pleases, he may dream that I make him this answer, that the certainty of things existing in rerum natura, when we have the testimony of our senses for it, is not only as great as our frame can attain to, but as our condition needs. For our faculties being suited not to the full extent of being, nor to a perfect, clear, comprehensive knowledge of things, free from all doubt and scruple; but to the preservation of us, in whom they are, and accommodated to the use of life; they serve to our purpose well enough, if they will but give us certain notice of those things which are convenient or inconvenient to us. For he that sees a candle burning, and hath experimented the force of its flame, by putting his finger in it, will little doubt that this is something existing without him, which does him harm, and puts him to great pain which is assurance enough, when no man requires greater certainty to govern his actions by than what is as certain as his actions themselves. And if our dreamer pleases to try whether the glowing heat of a glass furnace be barely a wandering imagination in a drowsy man's fancy; by putting his hand into it he may perhaps be wakened into

:

a certainty greater than he could wish, that it is something more than bare imagination. So that this evidence is as great as we can desire, being as certain to us as our pleasure or pain, i. e. happiness or misery; beyond which we have no concernment, either of knowing or being. Such an assurance of the existence of things without us is sufficient to direct us in the attaining the good, and avoiding the evil, which is caused by them; which is the important concernment we have of being made acquainted with them."

CHAPTER EIGHTH.

HABITS OF SENSATION AND PERCEPTION.

§. 97. General view of the law of habit and of its applications. THERE is an important law of the mental constitution, known as the law of Habit, which may be described in general terms as follows; That the mental action acquires facility and strength from repetition or practice. The fact, that the facility and the increase of strength, implied in HABIT, is owing to mere repetition, or what is more frequently termed practice, we learn, as we do other facts and principles in relation to the mind, from the observation of men around us, and from our own personal experience. And as it has hitherto been found impracticable to resolve it into any general fact or principle more elementary, it may justly be regarded as something ultimate and essential in our nature.

The term Habit, by the use of language, indicates the facility and strength, acquired in the way which has been mentioned, including both the result, and the manner of it. As the law of habit has reference to the whole mind of man, the application of the term, which expresses it, is of course very extensive. We apply it to the dexterity of workmen, in the different manual arts, to the rapidity of the accountant, to the coup d'œil or eye-glance of the military engineer, to the tact and fluency of the extemporaneous speaker, and

in other like instances. We apply it also in cases, where the mere exercise of emotion and desire is concerned; to the avaricious man's love of wealth, the ambitious man's passion for distinction, the wakeful suspicions of the jealous, and the confirmed and substantial benevolence of the philanthropist.

It is remarkable, that the law under consideration holds good in respect to the body, as well as the mind. In the mechanical arts, and in all cases, where there is a corporeal, as well as mental effort, the effect of practice will be found to extend to both. Not only the acts of the mind are quickened and strengthened, but all those muscles, which are at such times employed, become stronger and more obedient to the will. Indeed the submission of the muscular effort to the volition is oftentimes rendered so prompt by habit, that we are unable distinctly to recollect any exercise of volition, previous to the active or muscular exertion. It is habit, which is the basis of those characteristic peculiarities, that distinguish one man's hand-writing from another's; it is habit, which causes that peculiarity of attitude and motion, so easily discoverable in most persons, termed their gait; it is habit also, which has impressed on the muscles, immediately connected with the organs of speech, that fixed and precise form of action, which in different individuals gives rise, in part at least, to characteristics of voice. The habit in the cases just mentioned is both bodily and mental, and has become so strong, that it is hardly possible to counteract it for any length of time.The great law of Habit is applicable to all the leading divisions of our mental nature, the Intellect, the Sensibilities, and the Will; and as we advance from one view of the mind to another, we shall have repeated occasion to notice its influence. In the remainder of this chapter, we shall limit our remarks to Habit, considered in connection with the Sensations and Perceptions.

§. 98. Of habit in relation to the smell.

We shall consider the application of the principle of Habit to the senses in the same order, which has already been observed. In the first place, there are habits of Smell.-This sense, like the others, is susceptible of cultivation. As there are

some persons, whose power of distinguishing the difference of two or more colors is feeble; so there are some, who are doubtful and perplexed in like manner in the discrimination of odors. And as the inability may be overcome in some measure in the former case, so it may be in the latter. The fact, that the powers of which the smell is capable are not more frequently brought out and quickened, is owing to the circumstance that it is not ordinarily needed. It sometimes happens, however, that men are compelled to make an uncommon use of it, when by a defect in the other senses they are left without the ordinary helps to knowledge. It is then we see the effects of the law of Habit. It is stated in Mr. Stewart's Account of James Mitchell, who was deaf, sightless, and speechless, and of course strongly induced by his unfortunate situation to make much use of the sense we are considering, that his smell would immediately and invariably inform him of the presence of a stranger, and direct to the place where he might be; and it is repeatedly asserted, that this sense had become in him extremely acute.- "It is related, (says Dr. Abercrombie,) of the late Dr. Moyse, the well-known blind philosopher, that he could distinguish a black dress on his friends by its smell."

In an interesting account of a deaf, dumb, and blind girl in the Hartford Asylum recently published, statements are made on this subject of a similar purport.-"It has been observed, (says the writer,) of persons, who are deprived of a particular sense, that additional quickness or vigor seems to be bestowed on those which remain. Thus blind persons are often distinguished by peculiar exquisiteness of touch, and the deaf and dumb, who gain all their knowledge through the eye, concentrate, as it were, their whole souls in that channel of observation. With her, whose eye, ear, and tongue are alike dead, the capabilities both of touch and smell are exceedingly heightened. Especially the latter seems almost to have acquired the properties of a new sense, and to transcend the sagacity even of a spaniel."—Such is the influence of habit on the intimations of the sense under consideration.

§. 99. Of habit in relation to the taste.

The same law is applicable to the Taste, We see the re