Zoran,
Hi. Thanks for reading my essay and for the feedback!
The phrase "philosophical engineering" was just a catchy sounding phrase I liked that kind of summed up how I was talking about what are traditionally thought of as abstract concepts (existent states, spheres, etc.) but treating them as existent states and trying to build a model of the universe out of them.
I'm not familiar enough with Kant's philosophy to talk about "form" and "substance", but I think from what little I know, my existent states are like his "substance". I don't distinguish between abstract concepts and other, physical/concrete existent states. Abstract concepts are just existent states in the brain that are made of neuronal interconnections, molecules, etc., and traditional concrete objects are existent states outside the brain. No one has yet been able to show me where a Platonic realm is.
I agree totally that all these questions about what our existence is made of (it/bit, something/nothing, etc.) could also be answered theologically. I can't speak for whether or not the fqxi site would sanction essays related to theology, but I haven't seen any rules against it. My own views are more mechanical and materialistic, but when it comes to proof, I can't prove why there's something rather than nothing any more than any scientist or any theologian.
I look forward to your essay! Thanks!
Roger