This is a self-evident fact but it's not the most fundamental fact. We're not there yet but we've made a good start. So what is it about us that makes some actions good for us and some bad?
Well... I'm glad you thought my answer wasn't too bad.
And again, I'm not quite sure I perfectly understand you... but I'll try again. (But this time I'll try a different approach.

)
Is there "truth?" Or is "truth" whatever one perceives in their mind to be truth?
I believe the second (truth is whatever one perceives it to be) is extremely dangerous and prone to disastrous outcomes. I'll give two examples--the first most likely no one will disagree with. The second, though just as correct, sadly, many will disagree with.
#1--I don't care what one believes to be truth, if one jumps off the empire state building it is not going to go well for them. (Some would call it the law of gravity.)
#2 (and I'm using this to address what to me is an extremely sad reality)--If you go along with the idea that little ten-year old Johnny is really little ten year old Jenny, and allow him to, or encourage him to, cut off his penis and somehow get a vagina

, it will not make little ten year-old Johnny little ten-year old Jenny. It will only make him a mutilated ten-year old Johnny. And what makes it infinitely worse, it's not like cutting off you hair--that will grow back. (We know a 60 year old Johnny who did that very thing. To the public he is now Jenny. Privately, he told my wife and I that it was the worst thing he ever did.

)
Back to the point: There is truth!!! (At least in many aspects of life.)
Which brings me to the big question(s): What is truth? Where is it to be found? And, what is the source of it? (If there is a source.)
Got to run.
Fundamental truth #1--SELFISHNESS IS THE ROOT OF ALL EVIL.
("Prove all things; hold fast that which is good." {1 Thessalonians 5:21}