Is the world made of mind or matter?

Neither. The lowest layer of the world is the native observer, the one OPH's executable model runs, a bounded thing that keeps records and repairs disagreements with its neighbors, and that object is neither matter nor geometry and needs no mind. Matter comes out of it. A particle is a knot in the links between observers that no order of repair removes, and its mass is what holding the knot together costs at every step. Atoms are not observers. They are composed of such topological defects, and they become atoms when observers assign that meaning to them. Cells and readers are more complex observers, patterns selected on top of the stable laws. Mind arrives late, as a special case, with nothing added to the definition of an observer. Consciousness is owned boundary repair read from the inside, an observer reading its own state and spending its own budget on the result. Matter and mind are both patterns in what observers do.

Also in Chapter 1: Why Is the Universe So Hard to Reverse Engineer?, Chapter 3: Why Would a Universe Need Anybody In It?, Chapter 40: Does It Feel Like Anything, and What Is Left to Decide?.