366 On Method in Causal Research. 



" force." For where, indeed, would be the gain of inquiry into 

 the legitimacy of that which, when put forward as a cause, 

 serves only to make phenomena darker than before, by 

 attributing occult qualities to matter, and, in addition to this, 

 leaves one without a scientific method, entailing a fruitless 

 waste of intellectual energy. To those who might say that I 

 have assumed the idea of " force " to have more influence than 

 it actually has, I reply : — Recognize, then (for the sake of con- 

 sistency), the sole logical alternative that can replace it, viz. 

 the fact that the aether (or material agent in space) is the 

 source of the endless phases of motion developed in gross 

 matter on all sides — since the recognition of this fact is the 

 only proof that can be afforded that " force " (with its attendant 

 spiritualistic stores of energy) is rejected, not in profession, 

 but in practice. After the recognition of this fact, then the 

 inquiry into the mode or process involved in the derivation of 

 the motion from the material agent, becomes the next step, 

 which presents itself as an engineering problem of great 

 practical interest. 



I venture to think that the critical remarks made in this 

 essay will not be considered inopportune. May it not well be 

 conceivable that the immense success of experiment in this age 

 has caused the value of a strict and pure system of theoretic 

 reasoning to be less appreciated than would otherwise have 

 been the fact ? or that the danger of wandering from such a 

 system is greater (because its effects are less felt) when we 

 have the resource of experiment to fall back upon ? The 

 ancient Greeks, who had not recognized the worth of ex- 

 perimental research, were consequently thrown back upon 

 theoretic reasoning as a sole guide ; and the value of a strictly 

 rational system was every thing to them ; and the remarkable 

 progress they made in just theoretic views as to natural facts 

 is admitted (some of their fundamental deductions remaining 

 unshaken to this day). One may well imagine the confusion 

 that would have resulted, had the notion of a force " and the 

 attendant wandering into a maze of spiritualism, occurred to 

 them, without the backstay of experiment to put a curb on 

 these vagaries. 



Nevertheless, although the worth of experiment can scarcely 

 be overestimated, it is no doubt none the less true that the 

 general agreement upon a uniform and strict theoretic system 

 would be of immense practical value as an accompaniment to 

 this. Indeed, when one compares the enormous advantage we 

 possess in the present day in the extensive knowledge of facts 

 accumulated through years of experiment, with the disad- 

 vantage the ancients laboured under in their dearth of know- 



