This paper argues that Spinoza held substances other than God to be inconceivable. It uses this claim to develop a novel response to the Problem of Other Substances, the problem of explaining why some of Spinoza’s proofs for God’s existence cannot be used to prove the existence of a non-divine substance instead.

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)

We argue that prevailing definitions of Berkeley’s idealism fail to rule out a nearby Spinozist rival view that we call ‘mind-body identity panpsychism.’ Since Berkeley certainly does not agree with Spinoza on this issue, we call for more care in defining Berkeley’s view. After we propose our own definition of Berkeley’s idealism, we survey two Berkeleyan strategies to block the mind-body identity panpsychist and establish his idealism. We argue that Berkeley should follow Leibniz and further develop his account of the (...) mind’s unity. Unity—not activity—is the best way for Berkeley to establish his view at the expense of his panpsychist competitors. (shrink)

ABSTRACTMost of Spinoza’s arguments for God’s existence do not rely on any special feature of God, but instead on merely general features of substance. This raises the following worry: those arguments prove the existence of non-divine substances just as much as they prove God’s existence, and yet there is not enough room in Spinoza’s system for all these substances. I argue that Spinoza attempts to solve this problem by using a principle of plenitude to rule out the existence of other (...) substances and that the principle cannot be derived from the PSR, as many claim.Abbreviation: PSR: Principle of Sufficient Reason. (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)

This paper provides an interpretation and evaluation of Spinoza's highly original version of the ontological proof in terms of the concept of substance instead of the concept of perfection in the first book of his Ethics. Taking the lead from Kant'€™s critique of ontological arguments in the Critique of Pure Reason, the paper explores the underlying ontological and epistemological presuppositions of Spinoza'€™s proof. The main topics of consideration are the nature of Spinoza's definitions, the way he conceives of the relation (...) between a substance and its essence, and his conception of existence. Once clarity is shed upon these fundamental issues, it becomes possible to address the proof in its own terms. It is then easy to see that Kant's objections miss their target and that the same is true of those advanced by another of the ontological argument'€™s most famous critics, Bertrand Russell. Finally, several interpretations of Spinoza'€™s proof are proposed and critically evaluated; on all of them, the argument turns out to be either invalid or question-begging. (shrink)

Name der Zeitschrift: Deutsche Zeitschrift für Philosophie Jahrgang: 63 Heft: 3 Seiten: 476-496.

In Spinoza’s substance monism, radically different attributes constitute the essence of one and the same substance qua a strongly unified whole. Showing how this is possible poses a formidable Cartesian challenge to Spinoza’s metaphysics. In this paper I suggest a reconstruction of Spinoza’s notion of substance that meets this challenge and explains a major feature of this notion. I then show how this reconstruction can be used to resolve two fundamental problems of the Cartesian framework that pertain to Spinoza’s metaphysics. (...) On this basis, I then explain two further major features of Spinoza’s notion of substance. While my suggested reconstruction has all these advantages and accords well with Spinoza’s conceptual framework, it goes beyond what he explicitly says concerning substance monism. It is in the spirit of his metaphysical framework rather than in its letter. Thus, all I intend to show is that Spinoza has the conceptual resources for coming to terms with some of the deep problems that beset his metaphysics. (shrink)