One might object here that in order for humans to acquire knowledge of abstract objects in this way, they would first need to know that plenitudinous platonism is true. Linsky & Zalta respond to this by arguing that plenitudinous platonism (or in their lingo, principled platonism) is knowable a priori because it is required for our understanding of any possible scientific theory: it alone is capable of accounting for the mathematics that could be used in empirical science no matter what the