which a belief, whether positive or negative, commences a progress to a certainty which is correspondingly positive or negative.

Philosophically, twenty-five chances in one hundred give one fourth the confidence of certainty; fifty chances, one half; and seventy-five, three fourths; and these fractions symbolize these degrees of belief. But, in ordinary language, twenty-five chances in one hundred give half the confidence of negative certainty or of utter disbelief, and seventy-five chances half that of positive certainty; and the fractions one fourth and three fourths would symbolize a disbelief and a belief, each of which had half the confidence of certainty. Philosophically, the addition of one chance in the hundred would add one hundredth part of the confidence of certainty to the strength of our belief; according to the ordinary mode of thought, that addition would, as the case might be, either detract one fiftieth part of the confidence of certainty from the strength of disbelief, or add one fiftieth part of that confidence to the strength of belief. Our common conception of probability is more complex than that which we have termed philosophical; but it is necessitated by the practical question which continually presents itself, whether or not some statement has the majority of the chances in its favor.

No degree of probability can reach absolute certainty.

4. When probable judgments are combined, interesting questions arise concerning what is called "the calculation of chances." Such questions belong to logic rather than to the general philosophy of mind. We shall now add only one other remark respecting the nature of probability. It is that probable belief so differs from knowledge, or absolute certainty, that the latter can never be derived or developed from the former. For the ground of probability, though closely related to that of certitude, is distinguished by a radical peculiarity. Probability, like possibility, may prepare for knowledge, and be displaced by it, but it never can become the absolute certainty of fact. No matter how extreme the likelihood of a thing may be, no matter how small the proportion of the chances against it to the chances for it may be, still, so long as a thing is probable, there is a possibility of the opposite. Were there a thousand millions of chances for an event and only one against it, yet that one would render its non-occurrence perfectly possible.

We must, therefore, distinguish between that strong expectation which is sometimes called moral certainty, and the absolute confidence either of immediate cognition or of necessary inference. Any statement which conflicts with the perfect knowledge of reality must be unconditionally rejected; but a statement, however improbable, if it be not thus opposed to truth, should receive consideration if it be made seriously by intelligent persons. It would be very unlikely that a traveller should find a gold watch in the midst of the deserts of Sahara, but if he really found one all the antecedent improbability would disappear before the certainty of fact. We firmly believe that the sun will rise to-morrow, there is no probability that it will not; but there is no impossibility and no absurdity in the contrary supposition.

CHAPTER XXIII.

ATTENTION AND ACQUISITION.

1. HAVING considered the leading topics concerning thought and belief, the primary powers of mind,-we turn to contemplate those secondary powers whose operation modifies the workings of the primary. They may be enumerated as attention, acquisition, association, synthesis, analysis, abstraction, and generalization. Such, at least, are the powers whose modifying influence calls for special study.

Psychical

We begin with attention, that is, the power of energy, i. e., attention; for, apparently without exception, our facmental force ulties receive names which yet more properly designate the exercise of these faculties.

as exerted.

Every human spirit has a certain amount of psychical energy, or force, which is constantly more or less exercised in the activities of the soul's life, and especially in the activity of thought. This energy can be distinguished from the faculties or powers into which it enters. As general muscular strength can be distinguished from that power of involuntary motion possessed by the heart and other organs, from capabilities such as are shown in speaking, walking, running, handling, and so forth, from that acquired ability exhibited by experts in various arts and accomplishments, -and from the power of performing, without thought, actions which through habit have become automatic, so we distinguish psychical energy in general from the specific powers in which it is manifested. The reason of this is that the constitution of the soul gives a peculiarity of operation or function to every special power. We therefore distinguish from the faculty of thought that psychical energy necessarily belonging to it.

Yet this distinction does not of itself justify the conception of a faculty different from thought. It only brings into prominence the fact that a certain force is employed in all thinking. This energy varies in different persons, and in the same person at different times. The ideas of some men are fresh and vigorous, those of others slow and obscure; while the same person sometimes apprehends with ease, at other times with difficulty. All this does not indicate any specific faculty; it is simply a result of constitutional conditions and of general laws under which intellectual life is experienced.

Attention

special and

the power of

Involves a

There is, however, an exertion of energy in connecdefined. A tion with thought which indicates what we may propdeterminate erly style a faculty; for it is a determinate employment exertion of of power, and it accomplishes a special function. By thought. what seems a simple, ultimate law of spiritual activpower of de- ity, the soul can address itself with peculiar energy tention. to the observation of any object, or the consideration of any subject, which it may desire more fully to comprehend. The power thus exercised is called attention. Hamilton defines attention as "the concentration of consciousness on a smaller number of objects than constitute its widest compass of simultaneous knowledge." This description may be accepted with the addition that the effort of attention seems to increase, as well as to concentrate, the amount of mental force exercised at any one time. By "consciousness," in the above extract, we are to understand the general power of thought; and by "knowledge," thought in general. For we can concentrate and stimulate the power of thought when there may be no real objects whatever.

This special exertion of the power of thought in connection with some object or idea, or set of objects or ideas, is the essential constituent of attention. A sentinel, keenly vigilant for every indication of danger, might be said to exercise attention in the most general way possible, as his watchfulness would include all objects within the reach of his senses. The concentration of thought, though existing to some extent, would not be a prominent feature in such a case. But ordinarily the elements or objects to which our attention is directed are of a limited number, so that the special exercise of energy in connection with them has the effect of abstracting the force of thought from other objects; for every human spirit has only a limited amount of energy.

The successive consideration of objects, however vigorous it may be, cannot properly be called attention; it is simply energetic thought. In attention mental action is directed continuously to the same object or objects. The earnest consideration of subjects, successively, includes successive acts of attention. This faculty involves, as a subsidiary and constituent part of itself, a certain power of mental detention by which the same act of observing or thinking is repeated or prolonged.

Is attention

act? Is it

2. The most important point in the doctrine of a voluntary attention is that the operation of this faculty is to a considerable extent subject to the determinations of the will, that power of choice which is natural to the soul. According to Dr. Reid, "Attention is a voluntary act; it requires active exertion to begin and continue

truly an intellectual faculty?

it, and it may be continued as long as we will." Professor Stewart coincides in these statements; Hamilton controverts them. He says that there are three degrees of attention: "the first a mere vital and irresistible act; the second an act determined by desire, which, though involuntary, may be resisted by our will; the third an act determined by a deliberate volition." To us a doctrine intermediate between the views of these eminent men seems reasonable.

We agree with Hamilton that there is a vital and irresistible exercise of energy in connection with all thought and perception, but do not think that this should be called attention. On the other hand, choice, properly so called, is not always necessary to the act of attention; this is sometimes controlled by desires or motive habits which prevail against our formal volitions. How often people say that they cannot help thinking of such and such objects! How often we find ourselves earnestly considering some topic simply because we have become interested in it, without any deliberate determination! Such facts indicate that attention is exercised in accordance with that motivity which may be the prevailing one at the moment, whether it be mere unformulated desire, or whether it have the more complex character of will, or purpose.

In this connection we may consider a question which has been sometimes raised, namely, whether attention, a power the exercise of which confessedly originates in the motive part of man's nature, is properly an intellectual faculty at all. If by the mental faculties we are to understand those only which are the immediate fountains of thought and belief, then neither attention nor any other of the secondary powers can be enumerated in this class; but if that is an intellectual faculty whose proper function is immediately to affect and modify the main work of the mind, then certainly all the secondary powers may be thus named.

This, however, must be allowed, that attention has two principal functions, and in this respect is unlike the other subsidiary powers, which have each but one. In addition to the modification of thinking and to contributing in this way to intellectual results, attention performs a practical part in connection with the consideration of motives, and is thus the principal instrument in the self-control and self-determination of spirit. Whatever government the will exercises over psychical life in general is exerted through this power, just as its dominion over physical life depends upon muscular energy. Attention, therefore, has a twofold character: in one use it is an intellectual faculty; in another it is part of the practical faculty, the faculty of action, as distinguished from that of thought. Attention is a mental

faculty only so far as it modifies the working and affects the results of the primary powers of mind. But we should notice that it retains this character, more or less, even while helping to constitute the faculty of action.

The impor

tention, and

The great importance of attention, in the system of tance of the our mental faculties, is evident from its very nature. faculty of at- It is a power whose use is at once most general and of its culti- most indispensable. All those facts, whether of the vation and material or the spiritual world, which constitute the employment. original basis of thought and knowledge, are definitely seized and ascertained only through attentive observation and reflection. Moreover, those faculties of recollection, reason, and imagination, which elaborate the materials possessed by the mind, demand the continual exercise of attention. Whenever this power intermits its action, mental progress ceases. Attention is the action of the frame which holds in place the warp of that cloth which the subtile machinery of mind is weaving. When this frame performs its part imperfectly, confusion immediately ensues. Attention also has an important relation to memory, though less directly than to the intentional operations of mind. The permanent acquisition of thought depends greatly, if not entirely, on the vigor with which it may be first entertained, which vigor is controlled by attention. Should we desire to impress some beautiful scene upon the mind, or to commit some valuable fact or truth to memory, we must regard it earnestly.

Such being the case, it is plain that this power should be assiduously cultivated by those who would hope for any worthy intellectual attainments. And in this we should be encouraged by the consideration that no faculty admits of growth and development more than attention. Every faithful scholar can testify of that wonderful increase in the ability for mental application which results from a thorough course of study. The opinion of some that "genius is nothing but a continued attention"-"a prolonged patience" is an extreme one. beyond question this faculty is an essential part of all true genius, and it is that element of mental greatness most within the reach of honest endeavor; it is also that of which great men themselves have been most fully conscious.

But

Sir Isaac Newton, when complimented on his marvellous achievements, replied that if he had made any discoveries, it was owing more to patient attention than to any other talent. Dickens ascribed his success to a very painstaking study of the characters and details of his stories. Sometimes, with eminent men, the abstraction of mind resulting from intense application to favorite subjects has rendered them well-nigh insensible to