Hello Marcel, Georgina, qsa, Rick and Henk.
Re "Relationship with the universe... Everything we know we learned from our interaction with the universe in the capacity of an observer...You exists, that's all. And existence is the most basic property to consider" (Marcel, 2 March, 20:20):
I argue (e.g. in my essay and posts in the 2012 FQXi essay competition) that apprehended information is subjective experience*. I also contend that information is physical and "the physical" is information. So I agree with you, Georgina and Marcel, about the primary importance of subjective experience/ information in every aspect of the universe.
But here I am interested in examining a different issue related to the topic of Tegmark's Mathematical Universe: the issue of how to interpret the components of "law of nature" mathematical equations. I assume that the 100 years of work by thousands of scientists has not been in vain: the type of equations that they have come up with DO represent fundamental reality and not just a human viewpoint, although the precise details of "random" quantum events cannot be represented symbolically by mathematical equations.
Re "Your example: E = mc2. This equation means: the invariant mass of a system is the total energy divided by the speed of light squared" (Henk, 2 March, 17:01):
Henk, I think you seem to have closed your mind to the possibility that the symbols in law of nature equations could be interpreted in any other way. I'm suggesting that such equations do not live inside a black box, immune from further investigation. I'm suggesting that what we have are:
1. Distinct symbols representing acknowledged aspects of the underlying reality (e.g. E and m, representing energy and mass information respectively)
2. Strings of symbols representing some sort of relationship or structuring of these acknowledged aspects of the underlying reality (e.g. E = mc2 or E2 = (pc)2 + (mc2)2 )
3. Distinct symbols representing this structuring or relationship, where it is clear that "=" represents a different type of thing to the symbols "+", "-", "テキ" and "テ--".
Take these "structuring" symbols away from law of nature equations and you are left with nothing: no interconnection or relationship, no "balance" between one category of information and other categories of information. I contend that that the symbols "+ - テキ テ--" and "=" represent vitally important aspects of the underlying reality that really exist, and should not be ignored or denied.
Rick and qsa, my contention is that no matter what type of mathematics, algebra or geometry you want to use to represent fundamental reality, and no matter what particular mathematical equations you use, the above issue is essentially the same.
Lorraine
* I mean information in appropriately integrated physical systems like particles, plant cells and people; but I don't include computers because:
1. Computers don't have the internal physical interconnections to allow subjective experience (subjective experience of a physical object being summary information about the surrounding reality and the internal reality of the physical object)
2. Computers only deal with REPRESENTED information not information per se.