506 THE PRINCIPLES OF SCIENCE. [chap. 



guiding clues, his experiments were like those of all the 

 alchemists, purely tentative and haphazard. While his 

 hypothetical and deductive investigations have given us 

 the true system of the Universe, and opened the way in 

 almost all the great branches of natural philosophy, the 

 whole results of his tentative experiments are compre- 

 hended in -a few happy guesses, given in his celebrated 

 " Queries." 



Even when we are engaged in apparently passive 

 observation of a phenomenon, which we cannot modify 

 experimentally, it is advantageous that our attention 

 should be guided by theoretical anticipations. A pheno- 

 menon which seems simple is, in all probability, really 

 complex, and unless the mind is actively engaged in 

 looking for particular details, it is likely that the critical 

 circumstances will be passed over. Bessel regretted that 

 no distinct theory of the constitution of comets hnd 

 guided his observations of Halley's cornet;^ in attempting 

 to verify or refute a hypothesis, not only would there be 

 a chance of establishing a true theory, but if confuted, 

 the confutation would involve a store of useful observa- 

 tions. 



It would be an interesting work, but one which T can- 

 not undertake, to trace out the gradual reaction which has 

 taken place in recent times against the purely empirical 

 or Baconian theory of induction. Francis Bacon, seeing 

 the futility of the scholastic logic, which had long been 

 predominant, asserted that the accumulation of facts and 

 the orderly abstraction of axioms, or general laws from 

 them, constituted the true method of induction. Even 

 Bacon was not wholly unaware of the value of hypothe- 

 tical anticipation. In one or two places he incidentally 

 acknowledges it, as when he remarks that the subtlety of 

 nature surpasses that of reason, adding that " axioms ab- 

 stracted from particular facts in a careful and orderly 

 manner, readily suggest and mark out new particulars." 



Nevertheless Bacon's method, as far as we can gather 

 the meaning of the main portions of his writings, would 

 correspond to the process of empirically collecting facts 



' Tyndall, On Cometary Theory, Philosophical Magazine, April 

 1869. 4th Series, vol. .xxxvii. p. 243. 



