Spinoza's Ethics self-consciously follows the example of Euclid and other geometers in its use of axioms and definitions as the basis for derivations of hundreds of propositions of philosophical si...

The tenth proposition of Spinoza’s Ethics reads: ‘Each attribute of substance must be conceived through itself.’ Developing and defending the argument for this single proposition, it turns out, is vital to Spinoza’s philosophical project. Indeed, it’s virtually impossible to overstate its importance. Spinoza and his interpreters have used EIp10 to prove central claims in his metaphysics and philosophy of mind (i.e., substance monism, mind-body parallelism, mind-body identity, and finite subject individuation). It’s crucial for making sense of his epistemology (i.e., Spinoza’s (...) account of knowledge and response to skepticism) and in resolving puzzles within the Ethics (i.e., explaining human ignorance of all but two attributes). Even those who do not attribute some of the above claims to Spinoza need EIp10 to defend much of what they believe about Spinoza’s system. This paper locates a previously unnoticed argument for this proposition in Spinoza’s Short Treatise on God, Man, and His Well Being. There, Spinoza shows himself concerned with a powerful and underappreciated form of philosophical skepticism, one with surprising echoes in the work of his contemporary Leibniz as well as in the later Wittgenstein. Spinoza’s introduction of E1p10 in the Ethics circumvents this form of skepticism, solving the problem the Short Treatise envisions while also explaining that text’s argument’s absence from the explicit justificatory structure of the Ethics. (shrink)

I defend a new reading of Spinoza's account of causation that reconciles the strengths of the mechanist and formal cause interpretations by locating instances of nature's fixed and unchanging laws inside individual natures; natures are efficacious because that's where the laws are. God's necessity, for instance, follows from certain logical principles contained within God's nature. Causes between finite particulars likewise stem entirely from finite natures. They do so, I argue, because finite instances of nature's fixed and unchanging laws are inscribed (...) within those natures. In each of these instances, effects follow from natures on account of laws contained within them. (shrink)

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)