I am wondering if the universe is as simple as possible, at least given the constraint that humans exist on Earth. This is my second attempt at this question, which was marked as too broad, since I had trouble explaining it the first time.

To try to be more clear, I'm going to use a story. In another system, suppose we discover the theory of everything, something like:

the next state in time is the sum of the three previous states modulo 10

so what we observe is:

1 1 2 4 7 1 2 0 3 5 8 3 ...

Let's say that what we recognise as life is the sequence "0 3 5 8 3" - then this is a pretty elegant way to generate it. But we would also exist if the rule was:

the next state in time is the sum of the three previous states modulo 10, or the sum of the previous 4 states if they are equal to 16.

Clearly the last rule is unnecessary complication for life to exist. That's what I'm looking for evidence of.

Since we don't have a theory of everything, this is hard to answer. But do we have any likely counter examples? Do we know of some extra terms in a physics equation that aren't necessary for life and also make our model more complicated?

If anyone can point me to some research in this area, I would appreciate it.

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    $\begingroup$ As far as I know, the second and third generations of fermions are pretty much useless. $\endgroup$
    – Javier
    Commented Oct 16, 2015 at 18:28
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    $\begingroup$ One wrinkle to this Q. There are results of the SM, such as higher order fermions as mentioned by @Javier, that may have no direct existential consequence for humans, but are in themselves integral to the self-consistancy of the SM, therefore in a sense, are necessary for human existence. Perhaps Devin is asking if any of the fundamental laws or constants are not critical. Say, suppose gravity were twice as strong? $\endgroup$
    – Eubie Drew
    Commented Oct 16, 2015 at 20:33
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    $\begingroup$ @Javier I'm not sure of the details (and maybe no one is), but those other generations have some effect on nucleosynthetic processes such as core-collapse supernovae. Tinkering with them could dramatically alter heavy element abundances. $\endgroup$
    – user10851
    Commented Oct 16, 2015 at 20:49
  • $\begingroup$ Even randomness has an explanation. $\endgroup$
    – raul
    Commented Oct 16, 2015 at 21:11
  • $\begingroup$ @Aabaakawad - As I understand it, those higher order fermions actually make the standard model simpler, since as you say they allow it to be self-consistent. So actually I'm looking for the opposite answer - an unnecessary complication or inelegance. $\endgroup$
    – akvadrako
    Commented Oct 17, 2015 at 8:14