 Whewell’s first explicit, lengthy discussion of induction is found in his Philosophy of the Inductive Sciences, founded upon their History, which was originally published in 1840 (a second, enlarged edition appeared in 1847, and the third edition appeared as three separate works published between 1858 and 1860). He called his induction “Discoverers’ Induction” and explained that it is used to discover both phenomenal and causal laws. Whewell considered himself to be a follower of Bacon, and claimed to be “renovating” Bacon’s inductive method; thus one volume of the third edition of the Philosophy is entitled Novum Organon Renovatum. Whewell followed Bacon in rejecting the standard, overly-narrow notion of induction that holds induction to be merely simple enumeration of instances. Rather, Whewell explained that, in induction, “there is a New Element added to the combination [of instances] by the very act of thought by which they were combined” (1847, II, 48). This “act of thought” is a process Whewell called “colligation.” Colligation, according to Whewell, is the mental operation of bringing together a number of empirical facts by “superinducing” upon them a conception which unites the facts and renders them capable of being expressed by a general law. The conception thus provides the “true bond of Unity by which the phenomena are held together” (1847, II, 46), by providing a property shared by the known members of a class (in the case of causal laws, the colligating property is that of sharing the same cause).