Common myths establish an immediate trust between strangers and allow for unimpeded cooperation.
That is why people who otherwise would kill each other work together and trust each other when they believe in the same religious or political dogma.
This of course has nothing to do if the underlying dogma is true or not.
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Cooperative myths do indeed establish trust between strangers but such a process is self limited if the myths are false.
Cooperation forms a foundation that society builds itself upon. It allows for the unfolding of potential into higher orders of development. If the shared beliefs are false, that foundation will eventually fail and the society with it.
With increasing cooperation the power and understanding of a society grows progressively with time. Such understanding will explore and and expose any demonstrable untruths in the shared belief structure.
When this happens the common basis for cooperation fails and the society fragments and starts the process of collapse.
What is universe changing, however, is an inclusive paradigm that allows for genuine total and voluntary cooperation that cannot ever be falsified with progress. This is what is achieved by grounding ones foundation for cooperation in God.
God
cannot be falsified,
is entirely consistent with our knowledge of truth,
and maximizes cooperation over time.
You are certainly free to reject God and attempt to ground your reality in some other faith. That is exactly what you have done with your embrace of nihilistic principles.
You can live your life as though your existence is simply chance.
You can deny any ultimate purpose to your existence.
You can even decide that you have no inherent value or worth.
In the long run, however, these are not viable beliefs. They have no future because they don't form the necessary foundation needed to sustain cooperation and hence life over time.