speaks of this "humble confession" as "characteristic of the man," but we do not find this view of the matter satisfactory. The question is a simple one. In what does scientific success or failure consist? Either word should have its own distinct meaning. If Lord Kelvin is to be counted among those who have failed, whom shall we put down as having succeeded? Sir Isaac Newton? But Sir Isaac Newton did not "penetrate the mystery of the constitution of matter," to use Prof. Gray's expression, any more than Lord Kelvin has done. He provided a formula which expressed one kind of action exerted by bodies on one another, but he gave no clew to the nature of gravitation. He worked out a great number of intricate questions in mathematical astronomy, but none of his solutions do more than correlate phenomena. We may admit him to have been a greater genius than Lord Kelvin; but that would not justify us in saying that the labors of the latter bore the stamp of failure. Each was successful in a high degree in what constitutes the true work of the scientific investigator, the reduction of phenomena to law: if either aimed at doing more than this he failed, but the failure was not a scientific one; it was the inevitable failure of the human mind in striving to transcend the region of cause and effect and the relation of subject and object.
We have only to consider for a moment in order to see and feel that so long as any one phenomenon or condition is recognized as the cause of any other, the secret of the universe has not been penetrated—we are as much in the presence of "mystery" as if we had a thousand or a thousand thousand separate causes to deal with. Our minds are 90 constituted that, while our whole consciousness depends on the recognition of difference, we have a constant craving for unification; we would fain, as it were, destroy that by which we live. It is the baffled desire for unification that gives us the sense of mystery; and when Lord Kelvin talks of "failure" he means no more than that he has not succeeded in merging effects into causes and causes into effects, and making a unity in which thought itself would disappear.
We think ourselves that the word is unfortunately used; for there are those who are on the watch to catch every confession or expression of weakness on the part of science. "The foremost physicist of the age," these will say, "confesses that all his labors of fifty years may be summed up in the one word 'failure'; that he knows no more to-day about the deeper questions of science than he did fifty years ago. Is it not plain that the Mosaic account of creation must be correct in all its details, and that men in general can not do better than submit themselves to ecclesiastical authority?" Perhaps the deductions may not be expressed in this broad and simple way; but such at least will be the drift of the argument. And yet the truth is that science is all the time doing all that it can reasonably be expected to do—revealing the order and relations of phenomena, detecting, by means of approved appliances, operations of Nature which had eluded previous observation and which must ever have eluded the unaided senses of man, opening wider and wider regions to human thought, and conferring upon mankind an ever-increasing mastery of the laws and resources of the physical world. It does all this by the aid of symbolical language and working hypotheses—in other words, by a kind of algebra of its own; and the utmost fault its critics can find with it is