You can derive it from yourself and not a greater ‘supernatural’ purpose. For example, I have accepted I will die and that there is no meaning to life, I might even be an anti-natalist, but that doesn’t mean I just give up and live in despair. I’m alive and so with that life I act in my own self-interest to make the world better because it’s what makes my existence have a meaning.
You can derive it from yourself and not a greater ‘supernatural’ purpose. For example, I have accepted I will die and that there is no meaning to life, I might even be an anti-natalist, but that doesn’t mean I just give up and live in despair. I’m alive and so with that life I act in my own self-interest to make the world better because it’s what makes my existence have a meaning.
“making the world better” is an intangible idea that you are choosing to believe in. If you get comfort from that faith then I’m happy for you