Spinoza on the Distinction Between Substance and Attribute

Abstract I examine Spinoza's claim in the Metaphysical Thoughts (CM) that the attributes of God are only distinguished by a distinction of reason. I contend that for Spinoza essential attributes, such as Thought or Extension, cannot be distinguished by Francisco Suarez's distinction of reasoning reason, as Martin Lin (2019) suggests, nor can he be using Suárez’ distinction of reasoned reason for this purpose, as Yitzhak Melamed (2017) believes. Since reasoning reason and the distinction of reasoned reason are the only two kinds of rational distinction available to Spinoza, it follows that for him the distinction between God's essential attributes in the CM cannot be a distinction of reason. But I show that Spinoza is not mistakenly using Suarez's distinction in the CM. Rather, I argue, Spinoza consistently follows Suárez and uses reasoned reason to distinguish between God's necessary properties and not between God's essential attributes.