Spinoza and the problem of other substances

Abstract

Most 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

François Lamy’s Cartesian Refutation of Spinoza’s Ethics

“…Smith's emendation of Gueroult (682-686) resembles my interpretation of the God response, for Smith emphasizes the particular status of the ens realissimum in Spinoza's argument for substance monism, along with the fact that its one-of-a-kind infinite nature must be expressible in 'irreducibly different ways' (686). Barry (2019) follows Smith here. Yet I go further than either Smith or Barry in arguing that the notion of God as the ens realissimum is central to Spinoza's considered concepts of substance and attribute.…”

“…26 There is little discussion in the literature on Spinoza and the principle of plenitude. Exceptions include: Lovejoy (1936); Donagan (1989); Lin (2017); Newlands (2018); and Barry (2019). 27 Donagan (1989) raises a similar objection.…”

‘Except God, no substance can be conceived’: Spinoza on other substances

“…And so Spinoza could seemingly use his demonstrations in E1p11 to establish the existence of this other substance, and then infer that God does not exist. The Problem of Other Substances (Garrett 1979(Garrett /2018Barry 2019) is to explain why Spinoza does not and could not do this.…”

“…The more common response, however, has been to argue that while these non-divine substances have consistent definitions, they are not really possible: something prevents their existence. Versions of this response have been put forward by Della Rocca (2002), Lin (2007) and Barry (2019).…”

“…It seems that several of Spinoza's arguments for the existence of God can be used to prove the existence of a non-divine substance instead. The Problem of Other Substances (Garrett 1979(Garrett /2018Barry 2019) is to explain why Spinoza does not and could not do this. This paper develops a novel response to this problem, based on the claims that non-divine substances are inconceivable and that every conceivable substance exists.…”