THE PHILOSOPHICAL WORKS. '63 



be investigated and recognised, reduces itself to this, that the 

 form nature and the phenomenal nature (so to modify, for the 

 sake of distinctness, Bacon's phraseology) must constantly be 

 either both present or both absent ; and moreover that when 

 either increases or decreases, the other must do so too. 1 Setting ; 

 aside the vagueness of the second condition, it is to be observed 

 that there is nothing in this criterium to decide which of two 

 concomitant natures is the Form of the other. It is true that in 

 one place Bacon requires the form nature, beside being con- 

 vertible with the given one, to be also a limitation of a more 

 general nature. His words are "natura alia quas sit cum 

 natura data convertibilis et tamen sit limitatio naturae notions 

 instar generis veri." 2 Of this the meaning will easily be ap- 

 prehended if we refer to the case of heat, of which the form is 

 said to be a kind of motion motion being here the natura 

 notior, the more general natura, of which heat is a specific limi- 

 tation ; for wherever heat is present there also is motion, but 

 not vice versa. Still the difficulty recurs, that there is nothing 

 in the practical operation of Bacon's method which can serve 

 to determine whether this subsidiary condition is fulfilled ; nor 

 is the condition itself altogether free from vagueness. 



To each of the three points of that which I have called the 

 practical criterium of the Form corresponds one of the three 

 tables with which the investigation commences. The first is 

 the table " essentke et praesentiae^ and contains all known in- 

 stances in which the given nature is present. The second is 

 the table of declination or absence in like case (declinationis 

 sive absentia) in proximo), and contains instances which respect- 

 ively correspond to those of the first table, but in which, not- 

 withstanding this correspondence, the given nature is absent. 

 The third is the table of degrees or comparison (tabula gra- 

 duum sive tabula comparative), in which the instances of the 

 given nature are arranged according to the degree in which it 

 is manifested in each. 



It is easy to see the connexion between these tables, which 

 are collectively called tables of appearance, " comparentiaB," and 

 the criterium. For, let any instance in which the given nature i 

 is present (as the sun in the case of heat, or froth in the case of 

 whiteness) be resolved into the natures by the aggregation of 

 which our idea of it is constituted ; one of these natures is 



1 Nov. Org. ii. 4, 13, 16. 2 Nov. Org. ii. 4. 



VOL. I. D 



