112 NOVUM ORGANUM 



it; secondly, he will be anxious that the prescribed method 

 should not restrict him and tie him down to peculiar means, 

 and certain particular methods of acting; for he will, per 

 haps, be at loss, and without the power or opportunity of 

 collecting and procuring such means. Now if there be other 

 means and methods (besides those prescribed) of creating 

 such a nature, they will perhaps be of such a kind as are in 

 his power, yet by the confined limits of the precept he will 

 be deprived of reaping any advantage from them; thirdly, 

 he will be anxious to be shown something not so difficult 

 as the required effect itself, but approaching more nearly to 

 practice. 



We will lay this down, therefore, as the genuine and per 

 fect rule of practice, that it should be certain, free and pre 

 paratory, or having relation to practice. And this is the 

 same thing as the discovery of a true form; for the form of 

 any nature is such, that when it is assigned the particular 

 nature infallibly follows. It is, therefore, always present 

 when that nature is present, and universally attests such 

 presence, and is inherent in the whole of it. The same 

 form is of such a character, that if it be removed the par 

 ticular nature infallibly vanishes. It is, therefore, absent, 

 whenever that nature is absent, and perpetually testifies such 

 absence, and exists in no other nature. Lastly, the true 

 form is such, that it deduces the particular nature from some 

 source of essence existing in many subjects, and more known 

 (as they term it) to nature, than the form itself. Such, then, 

 is our determination and rule with regard to a genuine and 

 perfect theoretical axiom, that a nature be found convertible 

 with a given nature, and yet such as to limit the more 

 known nature, in the manner of a real genus. But these 

 two rules, the practical and theoretical, are in fact the 



