3f ARCK fl. 1886.1
��901
��He doM not sUle whether there U Hny difference in elerstion or in character of soil st the comers of tbi* triftDgle; but, if ibere 1> none, then this observed difference of motion is highly inierestlng and impor- tant, and should be tested and verified in every possi- ble wfty by interchange of instnimenls, resetting of Ruppoits, etc, in order to be sure in every way that there is no ioc&l pecnliArity of Instrumcitt nr method of attachment to the soil. Doubtless this wit) have been fully attended to in Professor Milne's continu- ation of these intereatitig experiments.
H. M. Paul.
��The logic of the phyBical sciences will al- ways remain a fascinatiog field for the philo- sophic inquirer, and doubtless also for the special student of those at^'iences. The recent elforts towards a - reform in logic ' in Germany have not left this field untouched ; and one of the first in importance, atnong the bool^s that bear on the general topic, is the work whose title is given below. The author has quali- fied himself for the task by a lengthy study of the history of the development of his science, and he has the |>ower to suggest much more than he directly says. In short, we have here a man who combines dcfinitencas with depth of thought; and his book, whether useful or not to the specialists in mechanics, is surely very suggestive to the student of logic.
The author represents in his way the new empiricism of Germany, — a doctrine that has grown up out of a study of Kant and the Eng- lish philosophy combined, and that as certainly points hack again into the realm of specially philosophic discussion as it appears anxious to be forever beyond that realm. This new em- piiicism is much more suggestive than the older empiricism' of J. S. Mill. lie had founded all inductive interpretation of nature on the (Causal principle, and the causal princi- ple itself again on an inductive interpretation of nature. The new empiricism escajjes from tliis circle by assuming a relatively a priori principle in all induction, but seeks to remain empiricism still by making this principle no abstract axiom, but a sort of ultimate Ibi'm or tendency of intelligence, viz., the tendency to conceive of the facts of experience in l/ie most ecoiiomicai wa^. This interest in economy of thought shall, in the new empiricism, take the place of the old axiom of causality, and, in fact, of all the mysterious axioms of past logicians. This tendency to economy is to be
��the true a priori that Kant sought. It is lo give us no knowledge transcending esjierieDce. but only a necessary presupjiosition concerning experience. What for bare experience would seem a confused mass, becomes for the scien- tific thinker, by virtue of this tendency lo economy, a world of law. All t!»e laws are indeed statements of empirical fact; but the statements never could assume this form save by virtue of the efl'ort to economize thought.
Such is the general statement of the new empiricism. Our author, for the roost part, confines his use of it to his special task, and lets general pliilosophy as much as possible alone. Yet he cannot but constantly suggest to the reader the philosophic problems peculiar to his method. For the rest, he lays claim in the preface lo considerable relative originality in the development of his own doctrine. Be- fore Kirchboff and Helmholtz applied to me- chanical science the general theories of the new empiricism, Mach had outlined his views in a published essay. He is tlius entitled to individualcredit.andopenlo separate criticism.
Applied to mechanical science, the new em- piricism, as our author and KirchhotT have expressed it, lakes the form of declaring the purpose of mechanics to be, "the simplest possible description of the motions thai are in the world." Thus at a stroke the science is to be freed from all mysterious elements. Those old ideas of force, of inertia, and the rest, are to be defined afresh in such a way as to conform to this logical theorj-. The science is to have its two perfectly plain bases ; viz., experience of motion, of velocity, of direction, etc., and the effort to think this experience with the least effort and the greatest unity.
The historical form that Mach gives to his doctrine makes it esiwcially attractive and en- lightening; and we hope for much good etTect from this element in the book. Mechanical science, as Mach frequently repeats, bod its origin very plainly in the need of men whose handiwork, owing to its technical complexity, was difficult to describe to those new in the craft. The learner must be enabled to see the permanent elements of the experience of his crafl beneath, and in all their endlessly various applications ; he must be brought to an ' iiber- sichtliche erfassung der thatsachen ; ' hence the need of quite general and simple descrip- tions, applying to fundamentally important facts. Economy of description llius from the first becomes the artistic principle, as it were, of this technical instruction.
If this is the origin and general method of the science in its embryonic stage, the origin
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