Version: v1, Published online: 2016
Retrieved December 12, 2018, from https://www.rep.routledge.com/articles/thematic/mind-and-body-in-early-modern-philosophy/v-1
One could think of idealism as the opposite of materialism. A materialist such as Hobbes thinks that the world is made entirely of matter and that everything, including minds and their thoughts, is somehow constructed from that material stuff and its motions. A stereotypical idealist holds instead that what there are fundamentally are (immaterial) minds and their thoughts. Everything else, matter included, is somehow constructed from them (see Idealism).
Again, Leibniz provides a good example, though complexities of interpretation mean that it is not an entirely uncontroversial one. As Leibniz wrote to the Leiden professor Burcher de Volder (1643–1709) in 1704, ‘there is nothing in things but simple substances, and in them, perception and appetite’ (Leibniz  1989: 181). The states of simple substances are mental ones, perceptions and appetites – what we might call thoughts and desires. And Leibniz did not think that bodies were simple substances. So somehow – and how is a big question – he thought that the entire material world was founded solely in these simple thinking things.
One approach to that question (seemingly not Leibniz’s) would be to identify the material things with the perceptions that minds have of them. Such an approach seems to appear in the work of George Berkeley. Berkeley was another who held an idealist view, which he called immaterialism (Berkeley  1949). He argued against the existence of material substance, something that underlies and gives rise to qualities (and ultimately then perceptions). Instead, he argues, there are minds (or spirits) and ideas. Everyday objects are, in fact, ideas, not the (mysterious) material substances that philosophers have claimed they are. As one character summarizes the view toward the end of Berkeley’s Three Dialogues:
My endeavours tend only to unite and place in a clearer light that truth, which was before shared between the vulgar and the philosophers: the former being of opinion, that those things they immediately perceive are the real things; and the latter, that the things immediately perceived, are ideas which exist only in the mind. Which two notions put together, do in effect constitute the substance of what I advance.
Duncan, Stewart. Idealism. Mind and body in early modern philosophy, 2016, doi:10.4324/9780415249126-V043-1. Routledge Encyclopedia of Philosophy, Taylor and Francis, https://www.rep.routledge.com/articles/thematic/mind-and-body-in-early-modern-philosophy/v-1/sections/idealism-1.
Copyright © 1998-2018 Routledge.