Déscartes believed that our mind was separate from our physical being, that our thoughts, emotions, ideas etc were created in a "mind" that was somehow separate from our body and our brain. He described this as "dualism". The idea originally developed in the 17th century was generally accepted by philosophers for 300 years. It wasn't until Gilbert Ryle dismissed the idea as "The Ghost within the Machine" - the mind within the body.
Ryle's The Concept of Mind (1949) is a critique of the notion that the mind is distinct from the body, and a rejection of the theory that mental states are separable from physical states. In this book Ryle refers to the idea of a fundamental distinction between mind and matter as "the ghost in the machine." According to Ryle, the classical theory of mind, or "Cartesian rationalism", makes a basic "category-mistake", because it attempts to analyze the relation between "mind" and "body" as if they were terms of the same logical category. This confusion of logical categories may be seen in other theories of the relation between mind and matter. For example, the idealist theory of mind makes a basic category-mistake by attempting to reduce physical reality to the same status as mental reality, while the materialist theory of mind makes a basic category-mistake by attempting to reduce mental reality to the same status as physical reality of a special kind. It is, namely, a category mistake.
Arthur Koestler then wrote a book taking Ryle's ideas: "The Ghost in the Machine". Again from Wikipedia:
The Ghost in the Machine is a non-fiction work in philosophical psychology written by Arthur Koestler and published in 1967. The title is a phrase coined by the Oxford philosopher Gilbert Ryle to describe the Cartesian dualist account of the mind–body relationship. Koestler shares with Ryle the view that the mind of a person is not an independent non-material entity, temporarily inhabiting and governing the body. One of the book's central concepts is that as the human brain evolved, it retained and built upon earlier, more primitive brain structures. The work attempts to explain humanity's tendency towards self-destruction in terms of brain structure, philosophies, and its overarching, cyclical political–historical dynamics, reaching the height of its potential in the nuclear arms arena.
But the concept of dualism has been widely exploited in art - by musicians, writers and artists. It is hard to equate thought/emotion/idea as the (mere?) product of a physical act. Some wires buzzing in your head. And as I have noted here and elsewhere, sometimes it can be hard to equate the fact there is only ONE mind in (working?) your body. And then there's the sub-conscious...
Mixed media on Canvas