SECTION 6. THE PROGRESS OF METHODOLOGICAL THEORY. 47 



the sun of science had just risen; it was altogether impossible in Roger 

 Bacon's period when pioneers were groping to escape from the pitch-dark- 

 night and superstition of the early Middle Ages. (See also J. E. Sandys, 

 Roger Bacon, 1914; and S. Vogl, Die Physik Roger Bacos, 1906.) 



16. Descartes' method tends to lure us away from out- 

 ward nature, and lays the stress on speculatively obtained pro- 

 positions or general principles. The great desideratum, accord- 

 ing to the illustrious French philosopher, is to possess clear 

 and distinct 1 ideas, and to reject everything which does not 

 harmonise with these. Pursuing this method, we shall, he 

 assures us, discover the fundamentals of existence, and from 

 them all the other facts will be deducible. The vital step to 

 take is "to divest oneself of preconceptions and study propo- 

 sitions exhaustively and impartially, making as complete a sur- 

 vey of our material as possible, and simplifying our problems 

 to the uttermost. Induction is here the handmaid of deduction, 

 and the aim is to discover, right at the threshold, the highest 

 generalities, and utilise these for deductive ends. (Discourx 

 sur la methode, I, 19.) Leaving aside his solid contributions to 

 mathematics, Descartes' method has exerted but a feeble in- 

 fluence on scientific progress, for the sufficient reason that 

 terms such as Clear and Distinct, on which he places such 

 emphasis, do not admit of exact definition, that trains of 

 reasoning are even more dangerous to rely on than the per- 

 ceptions of the senses, and because he preferred reasoning from 

 speculative propositions rather than objective study, seeking in 

 this way to apply pre-scientific methods in a growingly scientific 

 age.' 2 Just as Bacon for all intents and purposes first developed 

 to a high degree the inductive method and over-stressed it, so 

 Descartes was virtually the first to emphasise the signal value 

 of deductive and mathematical treatment without appreciating 

 their severe limitations. In connection both with Francis Bacon 

 and Descartes it may not be amiss to notice that methodology 

 formed their principal life-interest. 



Bertrand Russell, in his Our Knowledge of the External World as a Field 

 for Scientific Method in Philosophy, 1914, appears to aim at reviving the 

 Descartian point of view: "The nature of philosophic analysis, as illustrated 

 in our previous lectures, can now be stated in general terms. We start 

 from a body of common knowledge, which constitutes our data. On 

 examination, the data are found to be complex, rather vague, and largely 

 interdependent logically. By analysis we reduce them to propositions 

 which are as nearly as possible simple and precise, and we arrange them 

 in deductive chains, in which a certain number of initial propositions 

 form a logical guarantee for all the rest. These initial propositions are 

 premisses for the body of knowledge in question. Premisses are thus 

 quite different from data they are simpler, more precise, and less affected 



1 Locke preferred "determinate or determined". (Essay on the Human 

 Understanding, Epistle to the Reader.) 



- Jevons says in this connection: "Descartes and Leibniz sometimes 

 adopted hypothetical reasoning to the exclusion of experitnental verifica- 

 tion." (Principles of Science, p. 508.) 



