NOVUM ORGANUM 13 



XII. The present system of logic rather assists in con 

 firming and rendering inveterate the errors founded on 

 vulgar notions than in searching after truth, and is there 

 fore more hurtful than useful. 



XIII. The syllogism is not applied to the principles of 

 the sciences, and is of no avail in intermediate axioms, 4 as 



and extension of induction, and when the propositions they embrace are founded 

 on an accurate and close observation of facts, the conclusions to which they 

 lead, even in moral science, may be regarded as certain as the facts wrested out 

 of nature by direct experiment. In physics such forms are absolutely required 

 to generalize the results of experience, and to connect intermediate axioms with 

 laws still more general, as is sufficiently attested by the fact, that no science 

 since Bacon s day has ceased to be experimental by the mere method of induc 

 tion, and that all become exact only so far as they rise above experience, and 

 connect their isolated phenomena with general laws by the principles of deduc 

 tive reasoning. So far, then, are these forms from being useless, that they are 

 absolutely essential to the advancement of the sciences, and in no case can be 

 looked on as detrimental, except when obtruded in the place of direct experi 

 ment, or employed as a means of deducing conclusions about nature from im 

 aginary hypotheses and abstract conceptions. This had been unfortunately the 

 practice of the Greeks. From the rapid development geometry received in their 

 hands, they imagined the same method would lead to results equally brilliant in. 

 natural science, and snatching up some abstract principle, which they carefully 

 removed from the test of experiment, imagined they could reason out from it all 

 the laws and external appearances of the universe. The scholastics were im 

 pelled along the same path, not only by precedent, but by~ profession. Theology 

 was the only science which received from them a consistent development, and 

 the d priori grounds on which it rested prevented them from employing any 

 other method in the pursuit of natural phenomena. Thus, forms of demonstra 

 tion, in themselves accurate, and of momentous value in their proper sphere, 

 became confounded with fable, and led men into the idea they were exploring 

 truth when they were only accurately deducing error from error. One principle 

 ever so slightly deflected, like a false quantity in an equation, could be sufficient 

 to infect the whole series of conclusions of which it was the base; and though 

 the philosopher might subsequently deduce a thousand consecutive inferences 

 with the utmost accuracy or precision, he would only succeed in drawing out 

 very methodically nine hundred and ninety-nine errors. Ed. 



4 It would appear from this and the two preceding aphorisms, that Bacon 

 fell into the error of denying the utility of the syllogism in the very part of 

 inductive science where it is essentially required. Logic, like mathematics, is 



