[4] Although he once characterized himself as a "pure metaphysician",[5] his work has influenced a variety of disciplines across the humanities, including philosophy, art, and literary theory, as well as movements such as post-structuralism and postmodernism.
During the Nazi occupation of France, Deleuze's brother, three years his senior, Georges, was arrested for his participation in the French Resistance, and died while in transit to a concentration camp.
His teachers there included several noted specialists in the history of philosophy, such as Georges Canguilhem, Jean Hyppolite, Ferdinand Alquié, and Maurice de Gandillac.
He kept his fingernails untrimmed because, as he once explained, he lacked "normal protective fingerprints", and therefore could not "touch an object, particularly a piece of cloth, with the pads of my fingers without sharp pain".
[22] Deleuze's works fall into two groups: on the one hand, monographs interpreting the work of other philosophers (Baruch Spinoza, Gottfried Wilhelm Leibniz, David Hume, Immanuel Kant, Friedrich Nietzsche, Henri Bergson, Michel Foucault) and artists (Marcel Proust, Franz Kafka, Francis Bacon); on the other, eclectic philosophical tomes organized by concept (e.g., difference, sense, event, economy, cinema, desire, philosophy).
Deleuze's main philosophical project in the works he wrote prior to his collaborations with Guattari can be summarized as an inversion of the traditional metaphysical relationship between identity and difference.
"[26] A Deleuzean idea or concept of difference is therefore not a wraith-like abstraction of an experienced thing, it is a real system of differential relations that creates actual spaces, times, and sensations.
According to Deleuze, the traditional image of thought, found in philosophers such as Aristotle, René Descartes, and Edmund Husserl, misconceives thinking as a mostly unproblematic business.
Truth may be hard to discover—it may require a life of pure theorizing, or rigorous computation, or systematic doubt—but thinking is able, at least in principle, to correctly grasp facts, forms, ideas, etc.
It may be practically impossible to attain a God's-eye, neutral point of view, but that is the ideal to approximate: a disinterested pursuit that results in a determinate, fixed truth; an orderly extension of common sense.
Deleuze rejects this view as papering over the metaphysical flux, instead claiming that genuine thinking is a violent confrontation with reality, an involuntary rupture of established categories.
[33] In it, he refers to epistemological paradoxes: in the first series, as he analyzes Lewis Carroll's Alice in Wonderland, he remarks that "the personal self requires God and the world in general.
But when substantives and adjectives begin to dissolve, when the names of pause and rest are carried away by the verbs of pure becoming and slide into the language of events, all identity disappears from the self, the world, and God.
For Deleuze, concepts are not identity conditions or propositions, but metaphysical constructions that define a range of thinking, such as Plato's ideas, Descartes's cogito, or Kant's doctrine of the faculties.
"[36] In Deleuze's view, then, philosophy more closely resembles practical or artistic production than it does an adjunct to a definitive scientific description of a pre-existing world (as in the tradition of John Locke or Willard Van Orman Quine).
In his later work (from roughly 1981 onward), Deleuze sharply distinguishes art, philosophy, and science as three distinct disciplines, each relating to reality in different ways.
"[38] For example, Deleuze does not treat cinema as an art representing an external reality, but as an ontological practice that creates different ways of organizing movement and time.
Guided by the naturalistic ethics of Spinoza and Nietzsche, Deleuze instead seeks to understand individuals and their moralities as products of the organization of pre-individual desires and powers.
[48] Similar considerations apply, in Deleuze's view, to his own uses of mathematical and scientific terms, pace critics such as Alan Sokal: "I'm not saying that Resnais and Prigogine, or Godard and Thom, are doing the same thing.
From the 1930s onward, German philosopher Martin Heidegger wrote in a series of manuscripts and books on concepts of Difference, Identity, Representation, and Event; notably among these the Beiträge zur Philosophie (Vom Ereignis) (Written 1936-38; published posthumously 1989); none of the relevant texts were translated into French by Deleuze's death in 1995, excluding any strong possibility of appropriation.
"[53]This mutual apprehension of a differential, Evental ontology lead both thinkers into an extended critique of the representation characteristic to Platonic, Aristotelian, and Cartesian thought; as Joe Hughes states: "Difference and Repetition is a detective novel.
"[54] Heidegger formed his critiques most decisively in the concept of the fourfold [German: das Geviert], a non-metaphysical grounding for the thing (as opposed to "object") as "ungrounded, mediated, meaningful, and shared"[55] united in an "event of appropriation" [Ereignis].
This evental ontology continues in Identität und Differenz, where the fundamental concept expressed in Difference and Repetition, of dethroning the primacy of identity, can be seen throughout the text.
Another parallel can be found in their utilization of so-called "generative paradoxes," or rather problems whose fundamental problematic element is constantly outside the categorical grasp fond of formal, natural, and human sciences.
For Heidegger, this is the Earth in the fourfold, something which has as one of its traits the behaviour of "resisting articulation," what he characterizes as a "strife";[58] for Deleuze, a similar example can be spotted in the paradox of regress, or of indefinite proliferation in the Logic of Sense.
[59] In the 1960s, Deleuze's portrayal of Nietzsche as a metaphysician of difference rather than a reactionary mystic contributed greatly to the plausibility and popularity of "left-wing Nietzscheanism" as an intellectual stance.
"[62]) In the 1970s, the Anti-Oedipus, written in a style by turns vulgar and esoteric,[63] offering a sweeping analysis of the family, language, capitalism, and history via eclectic borrowings from primarily Marx, Freud, Lacan, and Nietzsche, but also featuring insights from dozens of other writers, was received as a theoretical embodiment of the anarchic spirit of May 1968.
According to Pascal Engel, Deleuze's metaphilosophical approach makes it impossible to reasonably disagree with a philosophical system, and so destroys meaning, truth, and philosophy itself.
[71] Peter Hallward argues that Deleuze's insistence that being is necessarily creative and always-differentiating entails that his philosophy can offer no insight into, and is supremely indifferent to, the material conditions of existence.
They give examples of mathematical concepts being "abused" by taking them out of their intended meaning, rendering the idea into normal language reduces it to truism or nonsense.