Materialism is the doctrine that only matter is real. Hence minds are in brains, and mental activity is nothing but brain activity. This assumption conflicts with our own experience.
In his study of children’s intellectual development, the Swiss psychologist Jean Piaget found that before about the age of ten or eleven, European children were like “primitive” people. They did not know that the mind was confined to the head; they thought it extended into the world around them. But by about the age of eleven, most had assimilated what Piaget called the “correct” view.
But not all philosophers and psychologists believe the mind-in-the-brain theory, and over the years a minority has always recognized that our perceptions may be just where they seem to be, in the external world outside our heads, rather than representations inside our brains.
My own interpretation is that vision takes place through extended perceptual fields, which are both within the brain and stretch out beyond it. Vision is rooted in the activity of the brain, but is not confined to the inside of the head. Like Velmans, I suggest that the formation of these fields depends on changes in various regions of the brain as vision takes place, influenced by expectations, intentions and memories. These are a kind of morphic field and, like other morphic fields, connect together parts within wholes, and have an inherent memory given by morphic resonance from similar fields in the past. When I look at a person or an animal, my perceptual field interacts with the field of the person or animal I am looking at, enabling my gaze to be detected.
Our experience certainly suggests that our minds are extended beyond our brains. We see and hear things in the space around us. But there is a strong taboo against anything that suggests that seeing and hearing might involve any kind of outward projection. This issue cannot be resolved by theoretical arguments alone, or else there would have been more progress over the last century — or even over the last 2,500 years.