Spinoza introduces the model (exemplar) of human nature in the preface to Part 4 of the Ethics when setting forth his conceptions of perfection and goodness. Perfection, he explains, is often judged by recourse to an ideal or a model, for instance, when we judge the perfection of a house by comparing it to an ideal house. In the case of human artifacts, the model is determined by the intention or plan of the craftsperson. But we often judge the perfection of natural things in the same way, which mistakenly supposes that nature creates things in accordance with a plan, like a craftsperson. In this case, our model is based not on an intention or plan in nature, but rather on our own desires, preferences, and ideals. Furthermore, judging from models can also be mistaken because our models are often based on our general ideas of things, which report on our idiosyncratic experiences, rather than the essences of things (E2p40s1).