The anti-metaphysical argument against scientific realism is the following: Knowledge of unobservable entities implies metaphysical knowledge; There is no metaphysical knowledge. Therefore, there is no knowledge of unobservable entities. This argument has strangely received little attention in the profuse literature on scientific realism. This paper claims that the AMA is logically more fundamental than both the pessimistic meta-induction and the underdetermination argument. The second and main claim of this paper is that the instrumentalists’ use of AMA is incoherent. The gist (...) of my argument is that experimental knowledge requires minimally metaphysical knowledge, and that minimally metaphysical knowledge—when associated with empirical knowledge—suffices to yield a minimal knowledge of the unobservable. I then examine and reject two possible responses: minimally metaphysical instrumentalism and algebraic instrumentalism. (shrink)