RELATIVE IMPORTANCE OF DISCOVERIES.

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CHAPTER XIX.

RELATIVE IMPORTANCE OF DIFFERENT RESEARCHES AND

DISCOVERIES.

ONE of the commonest of mistakes and most injurious to a sound scientific judgment is neglecting to value different truths according to their relative degrees of intrinsic importance. It is, however, often very difficult to estimate these degrees in pure science, because there is at present no fixed standard of their value.

Our conceptions of the phenomena of the universe are continually trammelled by our personal relations to them, and we find it difficult to consider them apart from ourselves. Every scientific person, therefore, adopts a different standard by which to value new truths, and estimates them according to the relation they bear to himself, his occupation, and his views of nature; and nearly all commercial persons value them only according to the amount of immediate pecuniary benefit they confer on the trading community. Most persons also consider practical inventions to be of greater importance than abstract discoveries; but such discoveries often contain fruitful truths from which many inventions spring; as, for instance, that of voltaic electricity, which gave rise to electro-plating, and that of electro-magnetism which yielded the electric telegraph. Less than fifty years ago no extensive practical applications of electricity were known, and electricity itself was considered to be only a philosophical toy; but now its great value in the telegraph and in electro-plating is recognised by every civilised person. The discoveries of gutta-percha, india-rubber, and many

other substances have also given rise to a multitude of useful applications.

The intrinsic value of a scientific truth largely depends upon its total amount of informative power, and as each truth can only contain a definite quantity, it probably possesses a definite value. The total amount of informative power contained in every such truth consists of two parts, viz., that which we can perceive, and that which is hidden, the known and the unknown; and one great reason why we are so little able to determine the intrinsic value of truths, especially of newly-discovered ones, is because the proportion wrapped up in a latent state and incapable of being appreciated, is an indefinite amount, and very much larger than that which is manifest.

The apparent value of a scientific truth depends upon the amount of informative power manifest in it; and this continually increases, because we are enabled, by the application of knowledge and of intellectual processes, to evolve continually more knowledge from it. For instance, when the first fact of electro-magnetism was discovered, its apparent value to ordinary persons was extremely small, and only philosophers could guess that it was of great intrinsic worth, because they alone could perceive that it implicitly contained great stores of future available knowledge in a latent potential state; but now that the science of electro-magnetism has been evolved from it, and it has been applied in electric telegraphs and other ways useful to mankind, even ordinary persons begin to perceive its great importance.

The greater or less intrinsic value of a newly-discovered truth is judged of by its nature. If we adopt as the highest standard of importance that which conduces most to the progress of civilisation and the happiness of mankind, the most important discoveries are not necessarily

INTRINSIC VALUE OF DIFFERENT NEW TRUTHS. 191

those which produce the most immediate practical benefit, but those which will ultimately explain, co-ordinate, and include the greatest variety and number of facts. The discovery of the law of action of gravity is generally considered by scientific philosophers to surpass all others in importance, because of the great magnitude, variety, and immense number of facts which it explains. Adopting the above as a standard, we may reasonably conclude that the discovery of a new force is intrinsically more important than that of any law or mode of action of that force; and that of a new elementary substance is more important than that of either of its compounds; also that the discovery of a general principle of structure or action of material substances is of greater importance than that of any solitary instance of it. Faraday made many dis

coveries; but those of magneto-electric induction, the relation of magnetism to light, and the universality of magnetic action are considered the most important, because they consist of general principles governing many phenomena.

The discovery of a new general relation between two forces is very important: when we find out an idea by whose intervention we discover the connection of two others, this is a revelation of God to us by the voice of reason.' Newton, finding out intermediate ideas, that showed the agreement or disagreement of the ideas, as expressed in the propositions he demonstrated,' was led into the truth and certainty of those propositions."1

The essential reason why the discovery of general principles is of such relatively great importance is because the fundamental facts and principles of a science implicitly contain, in a latent state, all the minor truths which are

Whewell, pp. 511, 512.

afterwards evolved from them by intellectual processes. The man who discovers a great scientific truth, as Oersted discovered the fundamental fact of electro-magnetism or Faraday found that of magneto-electricity, may be considered to have rendered comparatively easy the discovery of all the scientific knowledge wrapped up in it. The man also who discovers a fact upon which is afterwards built a manufacturing process may be similarly considered to have laid the foundation, and thus rendered possible the existence and development, of that particular practical invention; for instance, I discovered that phosphorus was decolourised by chlorine, and rendered possible the present process of bleaching phosphorus based upon it.

Discoveries of great general principles are important also because they largely enable us to predict events and to foretell the probable effect of proposed new experiments. Men of science, both in experimental physics and chemistry, look forward to the time when those sciences shall, like astronomy, be placed upon a mathematical and mechanical basis, and when they shall be able to predict the phenomena of their respective subjects by means of geometrical and mechanical principles, as astronomers can in the case of eclipses, &c. It is partly this expectation which causes such great interest to be taken by scientific investigators in discoveries in molecular physics, especially those which reveal to us new principles of molecular motion or of internal structure of inanimate substances.

The more complex sciences, and particularly the concrete oues, are more liable than the elementary ones to yield inconclusive results, because of the greater degree of complexity of their phenomena; it is, however, always possible in every science, if a research has been carefully made, to draw from it conclusions which are proved by the evidence. Researches which yield only negative results

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are sometimes as valuable as some others which yield positive ones, because they enable us to form valuable conclusions. The disproof of a false belief or superstition sometimes conduces as much to the progress of civilisation and the well-being of mankind as the ascertainment of a new truth. In important cases, even results which only enable us to form a probable opinion are, in the absence of more certain knowledge, of great value. For instance, at present we know that the light of some of the whitest and brightest of stars, such as Sirius, yields only the spectrum of hydrogen, and it is therefore considered probable by some investigators that the other elementary bodies formerly present have been decomposed by the intense heat into that primal element; and as none of the heavenly bodies yield spectra of iodine, bromine, or chlorine, it is further considered probable that of all the elementary bodies those are the most easily decomposed by beat.

Special subjects occasionally acquire a temporary and fictitious degree of importance in consequence of having been neglected for a time and left behind in the stream of human progress. By being thus neglected, they retard, and ultimately stop, the progress of some of the more advanced subjects, and their development thus becomes a matter of necessity and importance. It is, however, not the subjects themselves, but their development, that is altered in importance. The intrinsic value of the subjects remains the same, because both the quality and quantity of the knowledge they contain is unaltered.