Atheism is not the opposite of theism, but a separate category altogether. It is a person who does not have anything in the category of beliefs of anything spiritual or supernatural. They are human minus God(s), shall we say.

Then I suppose we should look at other humans who are missing some normal property of humans, and I revert to the example I have used before, the ability to see the colour red, which a sizeable proportion of the population does not. Their reality is obviously different to that of you or me who can see red. Does this mean that they have a "closed mind" to the idea of redness? I suspect that depends on definitions, and perhaps on personalities. Will they believe other people who tell them about redness? They can never experience it themselves.

I think atheists are just like this. Many (probably most) humans have a foundational belief in God(s), but some do not. This does not mean that they necessarily have a closed mind, simply that their brains are different. Some (including perhaps those who contribute here) seem to be fascinated by the concept, but don't have it themselves and can't understand why others do.

I think it is just another example of diversity in humankind, just like right or left-handedness, or skin colour or eye shape. Interesting, but not terribly important and certainly not something which underlies their perception of reality at all. For them, it is just something they cannot understand or experience.

- a netfriend...