sesses it as well as man; and some of the inferior animals have it in much greater delicacy, acuteness, and vigour. Though a faculty of this description, sensation is that which supplies materials for the exercise of memory, forms the basis of judgment, and excites to action all those noble and sublime powers which place man so high in the scale of intellectual existence. It is the vestibule of our intellectual fabric-the portal through which our knowledge is principally received.

'Among the various phenomena,' says Dugald Stewart, which the human mind presents to our view there is none more calculated to excite our curiosity and our wonder, than the communication which is carried on between the sentient, thinking, and active principle within us, and the material objects with which we are surrounded. How little soever the bulk of mankind may be disposed to attend to such inquiries, there is scarcely a person to be found who has not occasionally turned his thoughts to those powers of perception, which seem to inform us, by a sort of inspiration, of the various changes which take place in the external universe.' The manner in which this faculty acts, or in which these effects are produced, appears to be beyond the grasp of our powers to ascertain; and we are, therefore, obliged to content ourselves with stating it as an ultimate law of the human mind, as gravitation continues to be considered a law of nature. Every perception of an internal object appears to be accompanied by some notion of the thing perceived, and by a strong and irresistible belief of its present existence, which is not resolvable into any other kind of evidence. The rudest savage, as he tracks the untrodden wilds of the forest, is as fully convinced of what he hears, sees, or feels, as the most expert logician; but both are alike incapable of giving any reason for their belief, beyond the consciousness of the perceptions. It must not, however, be supposed from this, that every person

has equally vivid or clear perceptions on all subjects. The eye of the painter readily perceives beauties, and the ear of the musician distinguishes sounds, which elude the perceptions of the greater part of mankind. Suppose, also, a watch to be submitted to the inspection of three different persons whose senses are equally perfect and vigorous. The first wholly without any knowledge of its purpose and movements; the second well informed, but not acquainted with its particular mechanism; the third perfectly familiar with all its parts; how different would be their perceptions! The first might be attracted by the beauty and regularity of its parts, but he would have no idea of their subserviency to each other, or to the general purpose for which it was designed. The second, from his general knowledge of mechanism, would have some notion of the various parts, and of their connexion with the object of its construction; but how this is attained by their combination, he would be at a loss to perceive. The third, however, from his previous habits, sees the whole at once, and readily comprehends what escapes the observation of the others. The perceptive powers are, therefore, capable of improvement by cultivation, and should form an object of great attention in all systems of early tuition.

Our sensations and perceptions furnish us with ideas only respecting the individuality of objects, and without reference to their relation to, or distinction from, the other surrounding phenomena. Every object is distinguished from all others by some characteristic properties of its own, which constitute its identity; and the mind is capable of considering the various qualities of each object apart, and thus ascertaining those which are peculiar to it, as well as those which it possesses in common with others of a like nature. This operation of the mind is denominated Abstraction: by it we obtain general ideas; for 'had we possessed no such faculty as ab

straction, it is evident that all our knowledge would have been limited to an acquaintance with individual beings, and individual facts. But the very essence of science consists in generalizing and reducing to a few classes, or general principles, the multitude of individual things which every branch of human knowledge embraces. Hence, without abstraction, science could have had no existence; and the knowledge of man would have been, like that of the lower animals, in which no traces of this faculty are discernible, circumscribed to an acquaintance with those objects and events in nature with which he was connected by a regard to his own preservation and well-being.' It is by the power of attending separately to the things which our senses present to us in a state of union, and limiting our attention to the attributes which belong to them in common, that we obtain the idea of number; for it is only when they are thus reduced to the same genus that we acquire the idea of plurality. That the power of abstraction is one of the most important of our faculties, and intimately connected with the exercise of all our reasoning powers, admits not of doubt.

None of our mental faculties are more familiar to the mind than memory; few of them are more early displayed, nor any more constantly exercised, than this. It is the power by which we have an immediate knowledge of what we have previously perceived, thought, or felt. The precise manner in which this effect is produced, cannot be explained: we feel ourselves possessed of a certain power by which we recal to mind past occurrences; but of the connexion between these occurrences, and the power by which they are recalled, we are totally ignorant. The evidence of memory, however, relative to past events, is altogether so indisputable, that we do not hesitate to rest the most important concerns

1 Scott's Intellectual Philosophy.

of life upon it. It always includes a belief of past existence, which forms a peculiar distinction between memory and the other faculties. It also supplies materials for the exercise of several of the other powers; for, unless these arise from the immediate perception of the moment, they must be drawn from the treasures of past knowledge, which it is the office of memory alone to record. It is from this operation of the mind that we derive our ideas of time or duration, as the past can only be distinguished from the present by a recollection of the interval that separates them. A person, therefore, destitute of this faculty, could never obtain any notion of either duration or motion; for the latter idea depends entirely upon that of succession, which can only be supplied by memory. 'The notion of a limited duration, which we distinctly remember, leads us, by a kind of necessity, to the admission of a duration which has no limits-which neither began, nor will have an end. In like manner, the notion of limited extension and magnitude, which we acquire by the senses, leads us to the belief of an unlimited extension, or of space which has no boundaries. Thus are ac

quired the notions of infinite space, and of infinite time, or eternity. It cannot, however, be pretended, that our finite capacities are capable of forming adequate conceptions of those immense and unbounded attributes; it can only be said, that there is less dif ficulty in conceiving infinite space, and infinite time, than in conceiving the final boundaries of space, or the beginning or end of time'.'

Scarcely any thing distinguishes men more from each other than the extent and correctness of their memories. One man readily imbibes the knowledge presented to his attention; but when he wishes to recal it for future use, it has vanished, like the morning dew. Another receives information with much

' Scott's Intellectual Philosophy.

more difficulty, but retains it with greater ease and certainty; while a more favoured few possess memories at once susceptible, retentive, and ready. The cultivation of so noble a faculty as the memory, and one so essential to every human attainment, is deservedly considered as an object of the first importance in the developement of our intellectual powers; and it has therefore been a subject of early and protracted investigation. The most rational means of improvement, however, must ever be a strict attention to the objects and operations of the other faculties, whether it be sensation, perception, consciousness, abstraction, or any other. Great care must also be taken to direct the memory to its proper objects, so that association may exercise its most beneficial influence in connecting the past with the present. By this means, the understanding is engaged in treasuring up materials for the future use of the reasoning powers; and thus it is that our mental faculties all mutually assist and improve each other. These arguments, therefore, lead us to this conclusion, that whatever system of education is most adapted for equally developing all the intellectual powers, best promotes the growth and perfection of each.

As abstraction enables us to analyze the objects which Nature presents, and make their various qualities and attributes separately the subjects of our thoughts; so, by the power of Association, we form these objects into classes, according to some resemblance they possess, or some accidental circumstance which causes them to be present to the mind at the same time. Every one must be conscious of the almost illimitable influence of this principle over all the movements of our thinking powers. No idea can be stored in the mind in so detached a state, as not to have others so connected with it, as to render them almost inseparable. It is this power which gives language all its meaning, its beauty, its force,