Deleuze...

Like Kant and Bergson, Deleuze considers traditional notions of space and time as unifying forms imposed by the subject. Therefore he concludes that pure difference is non-spatio-temporal; it is an idea, what Deleuze calls "the virtual". (The coinage refers not to the "virtual reality" of the computer age, but to Proust's definition of the past: "real without being actual, ideal without being abstract."^[14]) While Deleuze's virtual ideas superficially resemble Plato's forms and Kant's ideas of pure reason, they are not originals or models, nor do they transcend possible experience; instead they are the conditions of actual experience, the internal difference in itself. "The concept they [the conditions] form is identical to its object."^[15] A Deleuzean idea or concept of difference is not a wraith-like abstraction of an experienced thing, it is a real system of differential relations that creates actual spaces, times, and sensations.^[16]

14 Proust, Le Temps Retrouvé, ch. III: see the fourth line from the bottom of this page, or, in English translation, the thirteenth paragraph here.

15Desert Islands, p. 36.

16^ See "The Method of Dramatization" in Desert Islands, and "Actual and Virtual" in Dialogues.

Plane of immanence is a founding concept in the metaphysics or ontology of French philosopher Gilles Deleuze. Immanence, meaning "existing or remaining within" generally offers a relative opposition to transcendence, a divine or empirical beyond (constituting the basic divided line of metaphysics or experience which haunted philosophy for so long). Deleuze, however, employs the term plane of immanence as a pure immanence, an unqualified immersion or embeddedness, an immanence which denies transcendence as a real distinction, Cartesian or otherwise. Pure immanence is thus often referred to as a pure plane, an infinite field without substantial or consistent division. In his final essay entitled Immanence: A Life, Deleuze writes: "It is only when immanence is no longer immanence to anything other than itself that we can speak of a plane of immanence."^[1]

^ Deleuze, Pure Immanence, p.27

The plane of immanence is metaphysically consistent with Spinoza’s single substance (God or Nature) in the sense that immanence is not immanent to substance but rather that immanence is substance, that is, immanent to itself. Pure immanence therefore will have consequences not only for the validity of a philosophical reliance on transcendence, but simultaneously for dualism and idealism. Mind may no longer be conceived as a self-contained field, substantially differentiated from body (dualism), nor as the primary condition of unilateral subjective mediation of external objects or events (idealism). Thus all real distinctions (mind and body, God and matter, interiority and exteriority, etc.) are collapsed or flattened into an even consistency or plane, namely immanence itself, that is, immanence without opposition.