ABSTRACT
Ideas of space and duration are Locke’s first examples of simple modes, which are complex ideas formed ultimately from the mind’s operations on one kind of simple idea. Analysis of Locke’s accounts reveals two problems. First, simple ideas of extension and succession have parts, in tension with their supposed simplicity. Second, Locke does not consistently categorize the same spatial and temporal ideas as simple ideas. In this chapter, I address these problems by distinguishing two kinds of simple ideas. What I call ‘psychological simple ideas’ are simple ideas passively received from sensation or reflection. ‘Simple’ refers to homogeneous content and permits parts, but those parts are not discerned in passive perception. What I call ‘scientific simple ideas’ are philosophers’ ideas of the types of basic qualities and affections of the things that cause psychological simple ideas. I use this distinction to explain the differences in Locke’s lists of simple ideas.
