Where did consciousness come from, and what purpose does it serve? Some theorists argue that it evolved from our interactions with other people, as a tool for understanding them better. Others believe that it resulted from improved fluidity in the communications among specialized circuits in the brain, enabling them to share information more effectively. Still others argue that consciousness arose from the need to deceive ourselves so that we could deceive other people more effectively, or from the simple fact that humans have the power of locomotion, or are fairly large animals.

Among all of the philosophical approaches proposed over the centuries to try to solve the “hard problem” of human consciousness, dualism and materialism are two that have gained the support of a considerable number of thinkers. But many of these thinkers have felt the need to nuance these two general theoretical positions so as to address the criticisms that have been levelled at them.

For example, to avoid the pitfalls of substance dualism, some philosophers have proposed an approach called “property dualism”. Property dualism recognizes that everything consists of matter, but holds that matter can have two types of properties, physical and mental, and that the latter cannot be reduced to the former. Property dualism is also often referred to as “non-reductive physicalism”.

According to this approach, pain, for example, would have a physical property (the action potentials transmitted by the C nerve fibres that sense pain) and, at the same, a conscious mental property (the feeling of pain).