... instances in which it does not occur have nothing in common save the absence of that circumstance, the circumstance in which alone the two sets of instances differ is the effect, or the cause, or an indispensable part of the cause, of the phenomenon." (3) The Method of Residues: "Subduct from any phenomenon such part as is known by previous inductions to be the effect of certain antecedents, and the residue of the phenomenon is the effect of the remaining antecedents." (4) The Method of Concomitant Variations: "Whatever phenomenon varies in any manner whenever ... — History Of Modern Philosophy - From Nicolas of Cusa to the Present Time • Richard Falckenberg