This piece reflects on the concept of “undetectable” through the double lens of HIV/AIDS discourse and the metaphysics of Gottfried Wilhelm von Leibniz. With the advent of antiretroviral therapy treatments for HIV infection that effectively reduce one's viral load to levels that elude conventional testing, a new form of identity has been produced that collapses the categories of “positive” and “negative.” The undetectable person is at once neither and both, a curious indeterminacy that throws into question what we mean when we speak of our “status.” In his treatise The Principles of Philosophy; or, the Monadology (1917), Leibniz formulates an ontology based on the double operation of “continuous fulgurations,” or what Gilles Deleuze would later term “the fold.” Existence, for Leibniz, is a production of the multiple that entails a simultaneous merging and diverging, unification and differentiation. The theoretical site of this movement is the monad. The world is composed of an infinite field of monads, and every monad in turn contains the entire world. This paradox is resolved through metaphors of perception: each monad possesses an embodied optics, a zone of darkness and a view on the world. The undetectable, like the monad, is both object and process, unfolding on a field of vision.