Absent Blue Wax (Rationalist Empiricism)

Very well then; just this once let us give [the mind] a completely free rein, so that after a while, when it is time to tighten the reins, it may more readily submit to being curbed.

René Descartes, Meditations on First Philosophy

Tho' the instance is so particular and singular, that 'tis scarcely worth our observing, and does not merit that for it alone we should alter our general maxim.

David Hume, A Treatise of Human Nature

What is an "exemplary exception"? This would not be an exception that proves the rule—that merely refers us back to the rule's existence—nor would it be an exception that disproves the rule—in the manner, let's say, that the incest prohibition deconstructs a binary opposition between nature and culture. Rather, an exemplary exception (in philosophy) would be an exception that exemplifies the positive power of a system of thought to intuit its outside from within its own parameters, while retaining the sense of that outside as a real exception: to encounter an outside within the movement of thought, without thereby either absorbing or collapsing into it. An exemplary exception inhabits an extra-systemic yet intra-philosophical space, a space exterior and open insofar as unbounded by an envelope of conceptual systematicity, yet nevertheless determined in its contours by the edges of those philosophical systems that generate exceptions—that produce exteriorities precisely by constituting a field of internal coherence. It is within such a structured yet exterior space that I want to situate what I call rationalist empiricism.

In what follows I focus on two classic exemplary exceptions: Hume's missing shade of blue and Descartes' wax experiment. And I argue that to think these exemplary exceptions together is to think the pre-Kantian chiasmus of rationalism and empiricism. The occasion for this effort is not only the exigency of conversations among friends¹ but also the challenge of Quentin Meillassoux's After Finitude, one of the rare virtues of which is to imply that a return to Descartes must also entail a return to Hume, and vice versa.² While neither the conceptual itinerary nor the specific arguments of After Finitude will concern us for the moment, the basic methodological gesture of Meillassoux's book—its effort to think the compossibility of apparently opposed pre-critical systems, Cartesian rationalism and Humean empiricism—motivates my engagement with the co-implication of Descartes' wax experiment and Hume's missing shade of blue. And since this might also seem like a Deleuzian gesture, our two exemplary exceptions will enable us, in due course, not only to produce a conceptual figure of what Meillassoux terms "the paradox of manifestation"³ but to characterize the transcendental empiricism of Difference and Repetition as an unwitting theory of Absent Blue Wax.

In the texts of Descartes and Hume, both the wax experiment and the missing shade of blue are explicitly identified as exemplary exceptions, and both are disavowed as deviations from the main lines of the philosophical programs pursued by these thinkers. "But I see what it is," writes Descartes, before taking up a piece of wax, "my mind enjoys wandering off and will not yet submit to being restrained within the bounds of truth. Very well then, just this once let us give it a completely free rein, so that after a while, when it is time to tighten the reins, it may more readily submit to being curbed."⁴ "Tho' the instance is so particular and singular," writes Hume, after having introduced his missing shade of blue, "that 'tis scarcely worth our observing, and does not merit that for it alone we should alter our general maxim."⁵ Descartes demonstrates the cognition of res extensa by "purely mental scrutiny" (M, 21), but he does so by temporarily indulging his sensory perceptions. As a speculative counterfactual to his own theory of perceptions, Hume grants the mind's capacity to construct the idea of an entirely unperceived shade of blue—and then immediately dismisses this example of an idea without a corresponding impression as too singular to merit consideration.

Both of these...