I’ve recently been revisiting Foucault's Birth of Biopolitics lectures, a misnomer if ever there was one since much of the discussion is on neo-liberalism and Foucault never actually gets to biopolitics. Regardless, while going through this book again an important connection and/or difference between the projects of Foucault and Deleuze became clear to me, a difference with clear connections to Hume and Adam Smith. A couple of passages should give a sense of these connections.
Foucault describes the consequence of this methodological decision as it relates to his project as follows: "I have tried to grasp the level of reflection in the practice of government and on the practice of government itself." (p. 2). It is this relationship between practice and the level of reflection upon this practice that is key – mirroring in profound ways the Humean distinction between impressions and impressions of reflection (of which more another time). As one reads Foucault, what becomes clear is that what Foucault is doing is engaging in an analysis of the multiplicity of practices with respect to governmentality and economics, as he had also done in his analyses of madness, medecine and the penal system, and the reflection upon these practices is understood by Foucault as the determinations and determinable projections of an indeterminate multiplicity of practices. This becomes clear by the end of the Biopolitics lectures when Foucault describes the state of economic man as being "situated in what we could call an indefinite field of immanence which...links him, in the form of dependence, to a series of accidents, and ... links him, in the form of production, to the advantages of others." (277). The result is a non-totalizable field of immanence, an indeterminately determinable multiplicity of practices and relationships that prevents a complete, synoptic view. In short, our particular, individual interests, are the consequence of a multiplicity of contingent causes that eludes any totalizing grasp. And yet, Foucault argues, "all these indefinite features of his [the economic man’s; J.B.] situation found, as it were, the specifically individual calculation that he makes; they give consistency, effect, insert it in reality, and connect it in the best possible way to the rest of the world. So, we have a system in which homo œcinomicus owes the positive nature of his calculation precisely to everything which eludes his calculation." (277). Foucault then goes on to cite Smith's famous Wealth of Nations passage from Book IV, ch. 2, where Smith invokes the invisible hand to account for the wealth of nations that results from individuals pursuing their particular interests. What Foucault stresses from this passage, however, is that most readers of Smith give emphasis to the hand of the invisible hand, the guiding hand that connects and draws together the multiplicity of particular interests into a process that improves the wealth of the nation as a whole. For Foucault, by contrast, what is overlooked is precisely the invisible aspect of the hand, the fact that it eludes a clear grasp, that no individual, from their particular perspective, can ever assume the role of the guiding hand themselves.
Deleuze’s project follows Foucault’s in many important respects, and by developing a Humean transcendental empiricism as I understand it and have argued for it elsewhere (here), Deleuze in effect generalizes Foucault’s historicized notion of the relationship between an indeterminate multiplicity and an actual, determinate reflection and calculation. This approach was already apparent in Deleuze’s 1959-60 lectures on Rousseau (here), and to which I thank Christian Kerslake for bringing to my attention, where Deleuze stresses that for Rousseau the state of nature is most significantly a “dependency on things,” and it is this that is natural (p. 5, translations mine). As Deleuze puts it, “what is natural is no longer the primitive, but rather the development that begins from the origin and follows the direction virtually contained in the origin.” The state of nature, then, is not a state but a process, or “a virtual and genetic state,” (ibid.) and thus “the state of nature is real as a point of departure for the movement from which a person becomes themselves.” This becomes the basis for Rousseau's critique of both Hobbes and Locke, as Deleuze reads it, in that both Hobbes and Locke presuppose an already established rational person in the state of nature when for Rousseau such a person is the result of a natural process, and a process of education that is the subject of Rousseau's Emile: or on Education. And towards the end of the lectures Deleuze adds that for Rousseau “the natural law is not in the state of nature for it is a genetic development of virtualities beginning from the state of nature. The natural law presupposes the society in the sense that the virtualities are only realized in objective circusmatces that are in the society.” (p. 25). This last point is crucial. The virutalities of the state of nature are only genetic virtualities which do not predetermine their actualization, nor are they actualities themselves; rather, they are nothing less than the process of becoming actual within an objective set of social circumstances. They are only determinate as actual! The state of nature is thus, to bring Foucault’s distinction back in, the “indefinite field of immanence” to which is owed the “positive nature” of one’s determinate calculations and projections. For Deleuze this distinciton becomes, in his later writings, the well-known (or notorious depending on your perspective) distinction between the virtual and the actual. For Foucault, however, this distinction is a historical consequence of of the reflections upon the economic practices of the day. Deleuze, by contrast, uses the virtual-actual distinction as part of his effort to assemble a metaphysics of difference that is then used to understand all determinate reflections and calculations. Deleuze thus appears to build a metaphysics upon what Foucault understood to be merely a historical artifact, or we have between Deleuze and Foucault sharply different understandings of philosophical concepts: they are either historical or ahistorical. I think this is a false dichotomy and the more one presses the Humean reading of Deleuze (and Foucault), the more one can make the case that, paradoxical as it may seem, the more historical a concept is, the more ahistorical it is.