My argument for atheism +

[Belacqua]

Actually, arguments are needed for strong or positive atheism.  This is the claim 'Gods do not exist.'  It differs from weak or negative atheism which is, 'I do not believe that gods exist,' for which arguments are unnecessary.

For thinking adults in a society, arguments are also necessary for weak atheism.

It's just that the arguments seem so obvious to us that we may not recognize them as arguments. 

Suppose you're happily living your life as a weak atheist, and some weirdo comes along and tells you that God created the world in six days. If you accept this, you're not an atheist any more. If you reject it, you're still an atheist. Why would you reject it?

Probably you reject it because you are committed to two arguments (=standards of judgment, =reasons):

1) the Bible isn't a reliable source for scientific facts, and 
2) real science tells us that the world wasn't created in six days.

These are commitments that we have. We are very sure that they are true, and we use them to evaluate statements about miraculous interventions and Jesus appearing on pieces of toast, etc. 

In our time and place and social class, these things seem like such obvious truths that we barely think about them, and I have no intention of arguing against them. But they are still arguments.