Genealogy: Genealogy is a non-linear view of history. With genealogy, it is possible for alternative/multiple/branching histories to occur.
Historicism: Historicism is a viewpoint that places emphasis on the social context, with one event leading to another in a linear manner. From this viewpoint, something that may be true at one moment may not be true at another moment.
Eclecticism: Eclecticism draws from multiple concepts to create new concepts. It does not stay within any one theory, but applies aspects or ideas of styles from different theories.
“Since eclectic architecture is an architecture of connoisseurs and not of purists, it serves to protect architectural borrowings from questions of principle. Thus, we see one of the effects of Johnsonʼs multiple inversion. Eclecticism allows him to choose from history whatever forms, shapes or directions he wants.” (Peter Eisenman, Introduction)
“To see it, as Johnson encourages us to, as the result of an interplay of multiple, overlapping forces, is to perceive its fundamental modernism--original and traditional; autonomous and dependent. Johnson was not engaged in a recovery of the past; rather, operating within what was presumed to be a consolidated tradition, he demonstrated its fundamental heterogeneity.” (Owens, Philip Johnson: History, Genealogy, Historicism)
“The approach to the house through meadow and copse is derived from English Eighteenth Century precedent. The actual model is Count Pucklerʼs estate at Muskau in Silesia.”
and
“The idea of asymmetric sliding rectangles was furthest developed in the De Stijl aesthetics of war-time Holland. These shapes, best known to posterity through the painting of the late Piet Mondrian, still have an enormous influence on many other architects besides myself.” (Philip Johnson, House at New Canaan, Connecticut)
Johnson, in his eclectic approach, is not simply copying ideas from past designs. He shows that a design is not the result of a linear progression of ideologies, but will always reference different branches of designs throughout history, and employ these references to create something new.