So it is also in the sciences of chemistry and physics. There is nothing to prevent the chemist or the physicist from being a philosopher, but he is not compelled to be one. He may push forward the investigations proper to his profession regardless of the type of philosophy which it pleases him to adopt. Whether he be a realist or an idealist, a dualist or a monist, he should, as chemist or physicist, treat the same sort of facts in the same sort of a way. His path appears to be laid out for him, and he can do work the value of which is undisputed by traveling quietly along it, and without stopping to consider consciously what kind of a path it is. There are many who work in this way, and they succeed in making important contributions to human knowledge.
Such sciences as these I call the non-philosophical sciences to distinguish them from the group of sciences I have been discussing at length. What marks them out is, that the facts with which the investigator has to deal are known by him with sufficient clearness to leave him usually in little doubt as to the use which he can make of them. His knowledge is clear enough for the purpose in hand, and his work is justified by its results. What is the relation of such sciences as these to philosophy?
79. THE STUDY OF SCIENTIFIC PRINCIPLES AND METHODS.—It is one thing to have the instinct of the investigator and to be able to feel one's way along the road that leads to new knowledge of a given kind, and it is another thing to have the reflective turn of mind that makes one clearly conscious of just what one has been doing and how one has been doing it. Men reasoned before there was a science of logic, and the sciences made their appearance before what may be called the logic of the sciences had its birth.
"It may be truly asserted," writes Professor Jevons,[1] "that the rapid progress of the physical sciences during the last three centuries has not been accompanied by a corresponding advance in the theory of reasoning. Physicists speak familiarly of Scientific Method, but they could not readily describe what they mean by that expression. Profoundly engaged in the study of particular classes of natural phenomena, they are usually too much engrossed in the immense and ever accumulating details of their special sciences to generalize upon the methods of reasoning which they unconsciously employ. Yet few will deny that these methods of reasoning ought to be studied, especially by those who endeavor to introduce scientific order into less successful and methodical branches of knowledge."
Professor Jevons suggests that it is lack of time and attention that prevents the scientific investigator from attaining to a clear conception of what is meant by scientific method. This has something to do with it, but I think we may also maintain that the work of the investigator and that of the critic are somewhat different in kind, and require somewhat different powers of mind. We find a parallel to this elsewhere. Both in literature and in art men may be in the best sense productive, and yet may be poor critics. We are often wofully disappointed when we attend a lecture on poetry by a poet, or one on painting by an artist.
It may be said: If what is maintained above regarding the possibility of prosecuting scientific researches without having recourse to reflective thought is true, why should the man of science care whether the principles and methods of the non-philosophical sciences are investigated or are merely taken for granted?
I answer: It should be observed that the statements made in the last section were somewhat guarded. I have used the expressions "as a rule" and "usually." I have spoken thus because one can work in the way described, without danger of error, only where a beaten track has been attained and is followed. In Chapter XVI it was pointed out that even in the mathematical sciences one may be forced to reflect upon the significance of one's symbols. As I write this, a pamphlet comes to hand which is concerned to prove that "every cause is potentially capable of producing several effects," and proves it by claiming that the square root of four ([square root symbol]4) is a cause which may have as effect either two (2) or minus two (-2).
Is this mathematical reasoning? Are mathematical relations ever those of cause and effect? And may one on the basis of such reasonings claim that in nature the relation of cause and effect is not a fixed and invariable one?
Even where there is a beaten track, there is some danger that men may wander from it. And on the confines of our knowledge there are fields in which the accepted road is yet to be established. Science makes constant use of hypotheses as an aid to investigation. What hypotheses may one frame, and what are inadmissible? How important an investigation of this question may be to the worker in certain branches of science will be clear to one who will read with attention Professor Poincaré's brilliant little work on "Science and Hypothesis." [2]
There is no field in art, literature, or science in which the work of the critic is wholly superfluous. "There are periods in the growth of science," writes Professor Pearson in his deservedly popular work, "The Grammar of Science," [3] "when it is well to turn our attention from its imposing superstructure and to examine carefully its foundations. The present book is primarily intended as a criticism of the fundamental concepts of modern science, and as such finds its justification in the motto placed upon its title-page." The motto in question is a quotation from the French philosopher Cousin: "Criticism is the life of science."