Rene Descartes's transformation of the notion of ideas deeply influenced subsequent thinking about their nature and epistemic significance in philosophical inquiry. This chapter addresses the imagistic nature of ideas and the conception of ideas as objects of immediate perception, including the related topics of objective being, act and act-object theories, and conceptions of perceptual immediacy. It considers issues related to the origins of ideas, including the topic of innateness, and a look at Locke's influential theory of how all ideas derive from experience. Nicolas Malebranche takes a different tack in his theory of ideas, by dissociating sensations and ideas. The theory at play in Malebranche's Vision in God doctrine is best described as an object theory of ideas. Accordingly, ideas function as perceptual objects, but not as perceptual acts – at least, not where perceptual acts are understood as modifications of our minds, or particular datable mental events.