Fascinating book and important reading. Pinter is a mathematics professor, and his approach is solidly grounded in cognitive science and evolutionary biology. The basic idea is that the mind organises cogntition in terms of gestalts, or meaningful wholes, which are the means by which even the simplest sentient creatures navigate the world. Even gestalts do not have objective existence - they are purely cognitive in nature - they are the fundamental constituents of lived reality.
It's written in a very spare style and doesn't engage in abstruse philosophical speculation, yet it has profound philosophical implications. To me, it conveys the framework for a credible form of philosophical dualism, although he doesn't explicitly say so in the text.
Highly recommended.