Wow, step away from a thread for a day or two and it totally morphs into something else...! :-)
I appreciate all your comments, and I'm particularly interested to learn more about biocentrism. What I find most intriguing -- as a linguist, a scientist, and someone who's been working and struggling with 'subjective reality' most of my life, since it's a central part of the Zen Buddhism I was brought up on -- is the ways in which our minds are organized.
What I'm working on -- with my questions about psychology, mathematics, and the scientific method -- is this:
IF subjective reality is 'true' in some deep sense, then reality is utterly created by our consciousness; BUT are there any structural limitations on that consciousness? Many people assume that if your mind creates your reality, then anything at all is possible, but it seems to me that's false.
Could you, for example, create a reality in which 1 + 1 = 3? Or Euclidean geometery does not work in an infinite flat plane? Or from linguistics: you might create a reality in which everyone spoke English, but could you create a reality in which everyone always spoke in C++? Or in which sentences had nouns, but no verbs? Or from psychology: could you create a reality in which your memory worked like a computer's direct access memory, instead of the human brain's distributed model?
What I'm saying is that the ways to be human appear to be infinite, but bounded. There are some things the human mind just doesn't do. Some of these things might be just inherent human limitation (like the inability to imagine infinity, or to speak always in C++); others (like mathematic truths) seem to be hard-wired into the universe itself.
THESE boundaries are the real rules of subjective reality. Or are they? What are they? And why are they there?