TRUTH 



and philosophers in regard to judgment and reasoning, 

 or all the subtler processes of thought; but they were 

 superficial and unpractised observers, and were barely 

 acquainted with experiment. In the Middle Ages scien- 

 tific work degenerated in both its aspects, as the domi- 

 nant creed demanded only faith and the recognition of 

 its supernatural revelation, and depreciated observa- 

 tion. The great importance of this as a foundation of 

 real knowledge was first appreciated by Bacon of 

 Verulam, whose Novum Organon (1620) laid down the 

 principles of scientific knowledge, in opposition to the 

 current scholasticism derived from Aristotle and his 

 Organon. Bacon became the founder of modern em- 

 pirical investigation, not only by making careful and 

 exact observation of phenomena the basis of all philos- 

 ophy, but also in demanding the supplementing of 

 this by experiment; by this experiment he understood 

 the putting of a question to Nature, as it were, which she 

 must herself answer — a kind of observation under defi- 

 nite and deliberate conditions. 



This more rigorous method of "exact observation," 

 which is hardly three hundred years old, was very 

 strongly aided by the inventions which enable the 

 human eye to penetrate into the farthest abysses of 

 space and the profoundest depths of smaller bodies — 

 the telescope and microscope. The great improvement 

 in these instruments during the nineteenth century, and 

 the support given by other recent inventions, have led 

 to triumphs of observation in this "century of science" 

 that surpassed all anticipation. However, this very 

 refinement of the technique of observation has its draw- 

 backs, and has led to many an error. The effort to 

 obtain the utmost accuracy in objective observation has 

 often led to a neglect of the part which is played by 

 the subjective mental action of the observer; his judg- 

 ment and reason have been depreciated in comparison 



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