There can be little disagreement about whether ideas of sense perception are, for Spinoza, to be classed as passions or actions—the former is obviously the correct answer. All this, however, does not mean that sense perception would be, for Spinoza, completely passive. In this essay I argue argues that there is in the Ethics an elaborate—and to my knowledge previously unacknowledged—line of reasoning according to which sense perception of finite things never fails to contain a definite active component. This argument (...) for activity in sense perception consists of two main parts: first, that ideas we form through sense perception have something adequate in them; second, that the adequate component is actively brought about. Discerning this line of thought connects to—and sheds some new light on—Spinoza’s general way of understanding ideas as entities involving activity. (shrink)