Commentators standardly ascribe to Spinoza a belief in an exceptionless conceptual closure of mental and physical realms: no intention can allow us to understand a bodily movement, no bodily injury can make intelligible a sensation of pain. This counterintuitive doctrine, most often now referred to as Spinoza's 'attribute barrier', has weighty repercussions for his views on intelligibility, nature of the mind, identity, and causality. I argue against the standard reading of the doctrine, by showing that it produces an inconsistent epistemological (...) picture, contradicting Spinoza's theory of mind and his commitment to universal intelligibility. The alternative account I propose is also philosophically more compelling and plausible as an account of thought in its essential intentionality. (shrink)