For the Thinking Man.

[Esquilax]

Atheism is a close ended belief system where everything is explained in terms of the natural order of things.

Gee, you think you'd, like, ask us what it is we believe, rather than just telling us. That's just rude.

And so ,no god or gods , only nature .

Not necessarily. So far you've said two sentences, and both have been false. That's not a good start.

But in nature all things are linked together and everything has precedence which can be traced back to the big bang.
But the problem for the godless is how to explain rational thinking.

Hoo boy, I can't wait to hear this one.

Since thoughts are events, all of our thoughts should be fully explainable in mechanical terms, and not to a person’s free-will .. But any thought which is not guided by what is “true” but only by mechanical , physical needs ,is not rational.

Except that truth is what conforms to reality, reality exists, and hence the thoughts one has about it are rational.

And if one comes to his beliefs and thoughts not because he chose it, but because it was all that the total universe would allow, then the" nature is everything"is, basically , self-defeating.
No belief is rational if it can be fully explained in terms of non-rational causes.
If all there is ,is materialism , then all beliefs can be fully explained in terms of non-rational causes.

This makes literally no sense at all. Try speaking clearly next time?

so if materialism is true, then no belief is rational. If any belief is based that no belief is rationally derived , then it should be rejected ... Therefore materialism ,atheism and nothing but nature should also be rejected ..

This is one of those gotcha questions that are so frustrating, but I won't get into that since I don't need to: given that you haven't bothered supporting any of your initial premises, you've just asserted them, they can be safely rejected out of hand.

Do you have any evidence for the word salad you said above?

but there's more : any notion of good and evil, right and wrong, love and hate, etc., must also be treated as mythical. nothing more than helpful ideas , but ideas with no existence ( ontology) of their own. Life would then be essentially meaningless since its ultimate goal is mere survival, an unattainable goal in a world where death is guaranteed and final.

Gosh, never heard this one before.

Good and evil can be formulated according to natural lines, simply by determining what is and isn't good for sentient beings and working from there. These aren't, like, big, complex things, dude. And your religion doesn't get to take ownership over ideas by fiat, either.