It’s pretty well known that Sartre had a large impact on the early formative years of Deleuze’s development. However, after Sartre’s (in)famous lecture, “Existentialism is a Humanism,” Deleuze felt that Sartre’s thought was becoming a bit cheap, a bit simplistic. However, it seems undeniable that, even though Deleuze explicitly requested that no one read his early works which were peppered with Sartrean influence, there was a spectral presence of Sartre’s thought in Deleuze’s work throughout his entire life.
With that said, one such area of disagreement, or perhaps simply incongruity, is regards to the nature of being-in-itself and the virtual. For Sartre, being-in-itself is defined in three maxims: it is. it is in itself. it is what it is. Simply stated, being-in-itself for Sartre is a complete unity, a whole, a static existence without difference. Thus, it is only when that mode of being which arises from being-in-itself – being-for-itself – differentiates the static existence of being-in-itself that difference is introduced. Being-for-itself (loosely stated, human consciousness) arises from being-in-itself (how Sartre does not explicitly make clear) and begins its activity of nihilation.
Deleuze on the other hand, comes at this from almost the completely opposite direction. For him, existence is positively understood as difference. Thus, difference is not understood negatively as that which is different between two identities. Rather, Deleuze wants to create an ontology that supports pure immanent difference as that which is ontologically prior. Thus, for him, all of existence is ontologically always to be understood as radical difference. However, the apparent world, the “real world,” seems to be riddled with identity – identified by identity. The history of human thought testifies to this – as Nietzsche so avidly testified. Human consciousness, in its quest for knowledge, has tended to reduce the wild, virtual world of difference into neatly compact identities. Thus, one of Deleuze’s main concerns was to palpate the “real world” of identity in order to allow the world of difference, the virtual, to break through and make itself known as that which lies beneath the “real world.”
Although these two seemingly divergent paths approach ontology from the opposite end, I think that there are more similarities than might be supposed at a surface-level reading. One such congruity concerns Spinoza-Hegel. Sartre was clearly influenced by Hegel – at least Kojeve’s Hegel. And Hegel was professedly carrying out a (somewhat) Spinozist task (Hegel was known to claim that in order to be a philosopher one must first be a Spinozist). Deleuze was too very interested in Spinoza’s thought – particularly, Spinoza’s ontological immanence and concept of Substance. Although the Sartrean understanding of being-in-itself seems to fit a bit closer with a conservative reading of Spinoza’s understanding of Substance, I think that Deleuze’s reading of Spinoza is also true to the latter. Although Substance is one for Spinoza (as Sartre would later carry forward in his understanding of being-in-itself), this totality is one with many levels – in the form of attributes and modes. These levels of being within Substance add to the complexity, the robustness, the difference that Deleuze later picks up in his writings.
Sartre too tries to posit a robustness to his ontology. However, it is generally understood as an additive task. For Sartre, being-in-itself is not pure difference in itself. Only being-for-itself can differentiate and demarcate particularities within being-in-itself. With that said, it is my belief – and this is the crux of the similitude between the two on this point that I want to begin to explore a bit further – that the reason that being-for-itself can differentiate is because being-in-itself, in its very existence as being-in-itself, is conceptually parallel to Hegel’s Absolute (and also very similar to Deleuze’s understanding of ontological difference). Although Sartre did not use the language of Absolute – such is much more properly Hegelian – the Hegelian legacy that he inherited from Kojeve seems to indicate that being-in-itself, even in its static existence, is necessarily transcendent in relation to being-for-itself. This paradox is the condition that allows Sartre’s being-for-itself to begin the process of nihilation itself. The existence, the robust existence of being-in-itself as Being that exceeds conscious apprehension comes out of the Hegelian-Spinozist legacy because phenomena (for Sartre) are moments of the Absolute’s self-unfolding. And as moments of the Absolute, as being being-in-itself it is necessarily something that cannot be exhausted by a momentary glance of human consciousness. There is always something more of being-in-itself to be apprehended. Although, different from Deleuze’s project, it this type of sentiment that lies deep in the pages of Being and Nothingness that open the door for a thinker to expand, redefine, and whittle away – enter Deleuze. With his emphasis on the positive difference of being itself, Deleuze ends up in a similar spot with Sartre: both thinkers are thinking from within immanence (Deleuze moreso) and are developing theories of immanence that break free from reductive tendencies while remaining thoroughly grounded.