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ET us now proceed to view the Intellect, or the thinking portion of the mind. The various faculties known under such names as Memory, Reason, Abstraction, Judgment, &c., are modes or varieties of Intellect. Although we can scarcely ever exert this portion of our mental system in separation from the other elements of mind, namely, Emotion and Volition, yet scientific method requires it to be described apart.

The full meaning and extent of this branch of the subject will be best seen from the ample detail that we are now to enter upon. The general characters that distinguish the Intelligence from the two other fundamental properties of mind may be expressed as follows:

1. The persistence or continuance of sensations and other mental states, after the withdrawal of the external agent, or stimulus, is a notable characteristic of the mind, not implied, as it seems to me, in the mere fact of consciousness. In consequence of this property we are enabled to live a life in ideas, in addition to the life in actualities.

2. The power of recovering, or reviving, under the form of ideas, past or extinct sensations* and feelings of all kinds, without the originals, and by mental agencies alone. These mental agencies are not included either in Emotion or in

Although we can hardly avoid using such terms as 'recover,' 'revive,' ' reproduce, recollect,' with reference to Sensations, it is to be borne in mind that there is a radical difference between the Sensation and the recollection of the Sensation, or what is properly termed the Idea. This fundamental and unerasable difference relates to the sense of objective reality which belongs to the sensation, and not to the idea. The sensation caused by the sight of the sun is one thing, and the idea or recollection of the sun is another thing; for although the two resemble each other, they yet differ in this vital particular. For many purposes, the idea can stand in the room of the sensation; the recollection of things often answers the same ends as the real presence. But there is one great question connected with our science, in which this distinction is the turning point of the problem, namely, the question as to our perception and belief of an external world. In discussing that subject, we shall have to attend closely to the circumstances that characterise a sensation as distinct from the counterpart idea.

Volition, and therefore require a place of their own. The two properties of continuance and recoverability by mental causes, which are probably at bottom the same property, make the fundamental and comprehensive distinction of Intellect.

3. The discrimination of conscious states, or the comparing of them one with another, with sense of agreement and difference, belongs to this department of mind. The fact of persistence is herein implied, for comparison cannot take place unless the traces of the past exist along with the present. I have already exemplified this power of discrimination, in speaking of the more intellectual part of the feelings of movement and sensations.

4 The acquired powers grow out of the properties of Intellect, and are not involved in Emotion, or in Volition.

5. Originality, or invention, is sustained by processes purely intellectual. By these processes, the compass of both Emotion and Action is enlarged in a most remarkable degree.

6. It is, I believe, a fact that Consciousness is not indispensable to the operations of Intellect. If so, this is a broad line of distinction between Intellect and the other regions of mind, for Consciousness makes up one of those regions, and is an essential part of the other.

Intellect may work in different degrees of combination with the remaining functions of mind. Science is the best example of its most pure manifestation. When blended with Emotion, the most interesting product is Fine Art; as the handmaid of Volition, directed to practical ends, it yields the higher combinations of Industry and Business.

* 'Mr. Stewart has made an ingenious attempt to explain sundry of the phænomena referred to the occult principle of habit, in his chapter on Attention, in the first volume of his Elements of the Philosophy of the Human Mind. It is to be regretted that he had not studied (he even treats it as inconceivable) the Leibnitzian doctrine of what has not been well denominated, obscure perceptions, or ideas—that is, acts and affections of mind, which, manifesting their existence in their effects, are themselves out of consciousness or apperception. The fact of such latent mental modifications is now established beyond all rational doubt; and on the supposition of their reality, we are able to solve various psychological phænomena otherwise inexplicable. Among these are many of those attributed to Habit.'SIR W. HAMILTON, Edition of Reid, p. 551.

LAWS OF ASSOCIATION.

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The revival, or reappearance of past states of mind by mere mental operations, is subject to fixed laws. These became the subject of investigation soon after the commencement of speculative thought. They are termed Laws of Mental Association, Suggestion, or Reproduction; and the first explicit statement of them is due to Aristotle.* I shall treat them as four in number, two being simple and fundamenal, and two complex. The exposition of Intellect in the present Book will be the exposition of these Laws.

* See Sir W. Hamilton's Contribution towards a History of the Doctrine of Mental Suggestion or Association.-REID, Note D.* *

CHAPTER I.

LAW OF CONTIGUITY.

1.

THIS associating principle is the basis of Memory, Habit,

and the Acquired Powers in general.

Sir

Mental Science have described it under various names. William Hamilton terms it the law of 'Redintegration,' regarding it as the principle whereby one part of a whole brings up the other parts, as when one syllable of a name recals the rest, or one house in a street suggests the succeeding ones. The associating links called Order in Time, Order in Place, and Cause and Effect are all included under it. We might also name it the law of Adhesion, Mental Adhesiveness, or Acquisition.

The following is a general statement of this mode of mental reproduction.

Actions, Sensations, and States of Feeling, occurring together or in close succession, tend to grow together, or cohere in such a way that when any one of them is afterwards presented to the mind, the others are apt to be brought up in idea.

There are various circumstances or conditions that regulate and modify the operation of this principle, so as to render the adhesive growth more or less rapid and secure. These will be best brought out by degrees in the progress of the exposition. As a general rule, repetition is necessary in order to render coherent in the mind a train or aggregate of images, as, for example, the successive aspects of a public way, with a sufficient degree of force to make one suggest the others at an after period. The precise degree of repetition needed depends on many circumstances, the quality of the individual mind being one.