As psychoanalysts continued to explore the glossed of unconscious motives, Otto Fenichel distinguished different sorts of rationalization both the justifying of irrational instinctive actions on the grounds that they were reasonable or normatively validated, and the rationalizing of defensive structures, whose purpose is unknown on the grounds that they have some quite different but somehow logical meaning.
12.
In the history of western thought, essence has often served as a vehicle for doctrines that tend to individuate different forms of existence as well as different identity conditions for objects and properties; in this logical meaning, the concept has given a strong theoretical and common-sense basis to the whole family of logical theories based on the " possible worlds " analogy set up by Quine.
