Philosophy of mind
Dualism is a set of views about the relationship between mind and matter (or body). It begins with the claim that mental phenomena are, in some respects, non-physical. One of the earliest known formulations of mind–body dualism was expressed in the eastern Sankhya and Yoga schools of Hindu philosophy (c. 650 BCE), which divided the world into purusha (mind/spirit) and prakriti (material substance). Specifically, the Yoga Sutra of Patanjali presents an analytical approach to the nature of the mind.
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.