But do you really speak about purpose?
I am not trying to be sarcastic with the question, but asking it honestly.
and my next question would be why do you ask or discuss purpose?
My purpose in life is to find out what the #%@* is happening in Lost.
Oh, you're talking about a higher purpose?
Hrmm…. discussions I've heard around secular humanism talk about the purpose of bettering humanity. And yes, we can do that by taking care of our families, personal satisfaction, etc., that's part of it. But there's also a deep-seeded need to take care of our species as a whole. It's instinctual, in fact. When a tragedy occurs, perfect strangers will risk their lives to help others.
But the need to better humanity can go even deeper. One of my favorite examples is the Constitution. This was not given to us by God on top of Mt Sinai, this was not transcribed through some angel, the Constitution was written by flawed, imperfect people (not all of them religious, at least conventionally) who did their best to figure out a system that would have the best chance of giving all of us freedom and liberty. And in bettering humanity, you make the world a better place for yourself to live in as well.
So the secular humanist would argue you don't need God or higher power to give purpose in your life. Finding your own path to better humanity and yourself (whether it's politics, songwriting, teaching, firefighting, whatever) is why atheists discuss purpose.