Despite the necessary connection the mind has with the body, argued Spinoza, sensation and imagination are inherently limited. The idea of substance qua substance must be a perfect unity. However, the idea which constitutes the human mind is complex—not a unity but a plurality of ideas. That idea is therefore confused, rather than clear and distinct. Clear and distinct understanding, on Spinoza’s account, must partake of the unity of the idea of substance, and not of the fragmentary nature of th