Dear Alma,
Thank you for your interesting comments on my essay. I just read yours with great interest and I'll be posting on your forum soon.
You are right: my essay stems from a long personal chain of thought, going back to 1986 when I was a graduate student in Astronomy at Harvard University. Rudy Rucker's book "Infinity and the Mind" introduced me to ideas that became the core of the way I think about the world: (i) the fact that the largest possible kind of infinity, Absolute Infinity, contains no information beyond the mere fact that it exists (like Borges' Library of Babel contains no information when taken as a whole), and (ii) the idea that our consciousness is the fundamental level of reality, and that ultimately (in a timeless, fundamental way) we all experience the same consciousness (when you strip it of all contingent, temporary details, your "I" is the same as my "I"). Over the next few years, I developed on my own many of the ideas that I put forward in my essay: Absolute Infinity, self-existing by necessity, generating an infinite multiverse where I exist simultaneously in an infinite number of different contexts, all these "I" being different yet the same. I soon found out (as Tegmark did --- see his book) that virtually all physicists see those ideas as unscientific, unwarranted and ultimately meaningless philosophical elucubrations. The indifference that I encountered at that time was certainly an important factor in my decision to leave academia (after finishing my master's degree in Astronomy, and doing another master's in History of science) and to go back to my home town of Montreal, where I teach introductory physics and astrophysics to 18- and 19-year-old students and pursue my personal cosmological and philosophical interests on my own time.
As the quotes in my essay testify, roboticist Hans Moravec had a huge influence on my worldview. It's when I read an article about him in Wired magazine ("Superhumanism" by Charles Platt, October 1995) that I first got acquainted with the idea that simulated realities might outnumber "ordinary" ones (an idea that became the core of Nick Bostrom's simulation argument), and the last chapter of Moravec's 1999 book "Robot: From Mere Machine To Transcendent Mind", available online on his website ("Simulation, Consciousness, Existence"), made all the pieces click together. Later, I was happy to see that Max Tegmark had become the champion of the mathematical universe hypothesis and its associated "mathematical democracy" argument: all mathematical structures (not just the one that corresponds to our universe) can equally give rise to physical universes.
If there's an unstated idea in my article, it's probably the fact that I think that the fundamental level of our reality is defined by our flow of consciousness (which is itself a mathematical structure): the regular and relatively simple physical universe that we find ourselves living in (itself a mathematical structure that embeds us) is the interface that allows our consciousness to witness each other and to communicate. As Moravec would say, "our existence is the product of self-interpretation in the space of all possible worlds", and "a possible world is as real, and only as real, as conscious observers, especially inside the world, think it is!"
You mentioned that you had trouble with the idea that a Maxiverse without any limitation on the kind of admissible mathematical structures (in particular, no conservation laws) could be a viable hypothesis. This is, of course, the main weakness of any theory where "anything goes": it seems plausible that if every possible universe exists, most universes that contain intelligences similar to our own will have some regularity (so life can be sustained), but not the rigid, universal, large scale regularity that we observe in our universe. As you expressed so eloquently in your own essay,
"We woke up in a place where so many things might have headed in a different direction, yet our universe is very well constrained. The constants are not changing and reality seems sturdy, like it will last forever. Everything insists to make perfect sense."
My ideas on this issue are still in flux. Yesterday, I read Alexey and Lev Burov's entry in this contest "Genesis of a Pythagorean Universe", where they present an interesting, potentially fatal flaw of Tegmark's Level IV universe (that applies even more to my own Maxiverse): according to them, the anthropic principle places limits on the stability of the laws of physics that are far looser that what we observe in our own universe. You should take a look at their essay if you have the chance. I am not convinced that they have an airtight case that condemns the Maxiverse hypothesis, but at least, contrary to what I wrote in my essay, I now believe that the Maxiverse hypothesis could potentially be proven false, which means that it is science after all! :)
I look forward to continuing this conversation here, and also in your forum after I comment on your essay.
Cheers!
Marc