I see what you mean absolutely. Given the vast scope of human intellectual constructs and considerations/musings such as ethics, aesthetic or art/beauty etc as you pointed out, they seem a far cry from fundamental physics. Almost or seemingly entirely separate/ devoid of influence or relevance in fact.
However, that being said I use the term "observer" in the loosest and most core sense, rather than by the higher order cognitive levels that derive all the extraneous features of the particularly human psyche.
The point I was arguing for pertained more to "accountancy" in the sense of unifying physical concepts without ignoring the measurers role (as we are physical beings subject to the same principles as the rest of the system.)
That is - when faced with the three physical domains of the specified scientific endeavour: 1). The Newtonian 2) the Relative 3). and The Quantum ... How does one measuredly refer all of these facets to the observer (the cognisant) whom studies them without factoring the measurer in?
It stands to reason that a theory that ties physics together cannot ignore the knot binder themselves-that is to say - the observer/measurer as well as the fundamental limitations - the boundaries, between them (consciousness) and the perceived external world - the subject of measurement.
We still do not know the fundamentals of consciousness/awareness nor how to conceptualise or understand them. Yet we can understand the products of such - art, literature, philosophy, ethics, etc. That made lead to an inherent sense of irrelevancy.
But at its base, the "physical" observer MUST interact with the "physical" environment at some boundary by some set rules and principles. Those are what i focus on - generalised as they may be.
So in a theory of everything/unifying theory -we must consider the external, yes - physics as it accords to the observer, as well as the observer in relationship to that physics. And I believe that is a matter of "perspective" - a phenomenon based on assumptions- the domain of the observer. Change those assumptions and you may get "the observer from the perspective of external physics" - a neccessary and complimentary opposite.
I don't believe the main physical domains can be reconciled without consideration for the role of the observer - we are not separate/isolated from the system we wish to understand. One slice of the cake cannot understand the whole without fitting their own piece into it.