Mind–body dualism
Ontological dualism makes dual commitments about the nature of existence as it relates to mind and matter, and can be divided into three different types:Substance dualism is a type of dualism most famously defended by René Descartes, which states that there are two kinds of foundation: mental and body. This philosophy states that the mental can exist outside of the body, and the body cannot think. Substance dualism is important historically for having given rise to much thought regarding the famous mind–body problem. Substance dualism is a philosophical position compatible with most theologies which claim that immortal souls occupy an independent realm of existence distinct from that of the physical world.
Depiction
A similar duality is proposed by the philosopher of art Richard Wollheim. He calls it 'twofoldness'. Our experience of the picture surface is called the 'configurational' aspect, and our experience of the object depicted the 'recognitional'. Wollheim's main claim is that we are simultaneously aware of both the surface and the depicted object. The concept of twofoldness has been very influential in contemporary analytic aesthetics, especially in the writings of Dominic Lopes and of Bence Nanay. Again, illusion is forestalled by the prominence of the picture surface where an object is depicted. Yet the object depicted quite simply "is" the picture surface under one reading, the surface indifferent to picture, another. The two are hardly compatible or simultaneous. Nor do they ensure a reference relation.