XXXI.] LIMITS OF SCIENTIFIC METHOD. 743 



law of chemistry is broken by tlie action of the nervous 

 cells, and no law of physics by the pulses of tlie nervous 

 fibres, but something requires to be added to our sciences 

 in order that we may explain these subtle phenomena. 



Now there is absolutely nothing in science or in scien- 

 tific method to warrant us in assigning a limit to this 

 liierarchy of laws. When in many undoubted cases we 

 find law overriding law, and at certain points in our 

 experience producing unexpected results, we cannot 

 venture to aftirm that we have exhausted the strange 

 phenomena whicli may have been provided for in the 

 original constitution of matter. The Universe might have 

 been so designed that it should go for long intervals 

 through the same round of unvaried existence, and yet 

 that events of exceptional character should be produced 

 from time to time. Babbage showed in that most profound 

 and eloquent work. The Ninth Bridgetvater Trtatise, that it 

 was theoretically possible for human artists to design a 

 machine, consisting of metallic wheels and levers, which 

 should work invariably according to a simple law of action 

 during any finite number of steps, and yet at a fixed 

 moment, however distant, should manifest a single breach 

 of law. Such an engine might goon counting, for instance, 

 the natural numbers until they would reach a number 

 requiring for its expression a hundred million digits. " If 

 every letter in the volume now before the reader's eyes," 

 says Babbage,^ "were changed into a figure, and if all the 

 figures contained in a thousand such volumes were arranged 

 in order, the whole together would yet fall far short of the 

 vast induction the observer would have had in favour of 

 the truth of the law of natural numbers. . . Yet sliall 

 the engine, ti'ue to the prediction of its director, after the 

 lapse of myriads of ages, fulfil its task, and give that one, 

 the first aufl only exception to that time-sanctioned law. 

 What would have been the chances against the aj)pearance 

 of the excepted case, inmiediately prior to its occurrence ? " 



As Babbage further showed,^ a calculating engine, after 

 ])roc('eding tlirongh any required number of motions 

 acccjnbng to a iirsL law, may be made suddenly to suffer 

 a change, so that it shall tiien com.mence to calculate 



' Ninth Bridge.watcr I'rcatise, p. 140. 

 2 IhiJ. pii. 34-^j. 



