Abstract
This article calls into question the notion that seventeenth-century authors such as Descartes and Leibniz straightforwardly conceived the mind as something "outside" nature. Descartes indeed did regard matter as distinct from mind, but the question then remains as to whether he equated the natural world, and the world of laws of nature, with the material world. Similarly, Leibniz distinguished a kingdom of final causes (pertaining to souls) and a kingdom of efficient causes (pertaining to bodies and motions), but the question remains as to whether he equated nature with the second kingdom alone, or included both kingdoms within nature. Although Kant sundered Leibniz's envisioned connection between the two kingdoms, even he did not place mind fully outside nature.