Editing Solipsism (section)

===Cartesian dualism===
There is another option: the belief that both ideals and "reality" exist. [[Dualism (philosophy of mind)|Dualists]] commonly argue that the distinction between the [[mind]] (or '[[idea]]s') and matter can be proven by employing [[Leibniz|Leibniz's]] principle of the ''[[identity of indiscernibles]]'', which states that if two things share exactly the same qualities, then they must be identical, as in indistinguishable from each other and therefore one and the same thing. Dualists then attempt to identify attributes of mind that are lacked by matter (such as privacy or intentionality) or vice versa (such as having a certain temperature or electrical charge).<ref>{{cite web|url = http://www.newdualism.org/papers/J.DePoe/dualism.htm|title = A Defense of Dualism|first = John M|last = DePoe|work = New Dualism Archive}}</ref><ref>{{CathEncy|wstitle=Dualism}}</ref> One notable application of the [[identity of indiscernibles]] was by René Descartes in his ''[[Meditations on First Philosophy]]''. Descartes concluded that he could not doubt the existence of ''himself'' (the famous ''[[cogito ergo sum]]'' argument), but that he ''could'' doubt the (separate) existence of ''his'' body. From this, he inferred that the ''person Descartes'' must not be identical to ''the Descartes body'' since one possessed a characteristic that the other did not: namely, it could be known to exist. Solipsism agrees with Descartes in this aspect, and goes further: only things that can be known to exist for sure should be considered to exist. ''The Descartes body'' could only exist as an idea in the mind of the ''person Descartes''.<ref>{{cite encyclopedia|url = http://www.iep.utm.edu/d/dualism.htm|encyclopedia = [[Internet Encyclopedia of Philosophy]]|title = Dualism and Mind|first = Scott|last = Calef|date = 9 June 2005}}</ref><ref>{{cite encyclopedia|url = http://www.iep.utm.edu/s/solipsis.htm|encyclopedia = [[Internet Encyclopedia of Philosophy]]|title = Solipsism and the Problem of Other Minds|first = Stephen P.|last = Thornton|date = 24 October 2004}}</ref> Descartes and dualism aim to prove the actual existence of reality as opposed to a phantom existence (as well as the existence of God in Descartes' case), using the realm of ideas merely as a starting point, but solipsism usually finds those further arguments unconvincing. The solipsist instead proposes that their own unconscious is the author of all seemingly "external" events from "reality".