We have seen in Chapter XVI that a work on logic may be a comparatively simple thing.  It may describe the ways in which men reason when they reason correctly, and may not go deep into metaphysical questions.  On the other hand, it may be deeply metaphysical.

When we approach the part of logic which deals with the principles and methods of the sciences, this difference is forced upon our attention.  One may set forth the assumptions upon which a science rests, and may describe the methods of investigation employed, without going much below the plane of common thought.  As a type of such works I may mention the useful treatise by Professor Jevons cited earlier in this chapter.

On the other hand, our investigations may be more profound, and we may scrutinize the very foundations upon which a science rests.  Both the other works referred to illustrate this method of procedure.

For example, in “The Grammar of Science,” we find our author discussing, under the title “The Facts of Science,” such problems as the following:  the Reality of Things; Sense-impressions and Consciousness; the Nature of Thought; the External Universe; Sensations as the Ultimate Source of the Materials of Knowledge; and the Futility of “Things-in-themselves.”  The philosophical character of such discussions does not need to be pointed out at length.

[1] “The Principles Of Science,” London, 1874, Preface.

[2] English translation, New York, 1905.

[3] Second edition, London, 1900.

VI.  ON THE STUDY OF PHILOSOPHY

CHAPTER XXII

THE VALUE OF THE STUDY OF PHILOSOPHY

80.  THE QUESTION OF PRACTICAL UTILITY.—­Why should men study philosophy?  The question is a natural one, for man is a rational being, and when the worth of a thing is not at once evident to him, he usually calls for proof of its worth.  Our professional schools, with the exception of schools of theology, usually pay little attention to philosophical studies; but such studies occupy a strong position in our colleges, and a vast number of persons not students in the technical sense think it worth while to occupy themselves with them more or less.  Wherever liberal studies are prosecuted they have their place, and it is an honored place.  Is this as it should be?

Before we ask whether any given study is of practical value, it is wise to determine what the word “practical” shall be taken to mean.  Shall we say that we may call practical only such learning as can be turned to direct account in earning money later?  If we restrict the meaning of the word in this way, we seem to strike a blow at liberal studies in general.

Thus, no one would think of maintaining that the study of mathematics is not of practical value—­sometimes and to some persons.  The physicist and the engineer need to know a good deal about mathematics.  But how is it with the merchant, the lawyer, the clergyman, the physician?  How much of their algebra, geometry, and trigonometry do these remember after they have become absorbed in the practice of their several callings, and how often do they find it necessary to use anything beyond certain simple rules of arithmetic?