What is the concept of atheism?

It's a belief. Atheism is the belief that there is no God. Practicing atheism just means not being involved in any religion and not believing in a God.

Actually, I don't think there is a concept, it is about a lack of concept. I don't think atheists attend meetings or have any kind of belief system at all. I feel sorry for them. They are missing so much that could give them a more positive life.

I also dislike the vocal atheists who have just made life miserable for those who do practice faith. Leave us alone. I feel my religious freedom has been stomped upon.

You don't have to do what we do or believe what we believe, but many people seem to want to treat people of faith rudely. If I were to want to pray in a school, who cares? It doesn't hurt anyone else. It I want to erect a menorah or a cross in my town, it doesn't injure you, just drive on by and ignore it. Why make a stink about it and cause unhappiness. Life is too short to bother with stuff like that, we all have so many other issues that are important.

I think the basic 10 commandments of the bible and the golden rule are essential for good conduct, weather you belief or do not believe and I think there are some people out there who sure could use a bit better conduct, morals and manners.

The golden rule, "Treat people as you would like to be treated" is often ignored by some "in your face" atheists. From the 10 commandments, "do not bear false witness" (do not lie) as well as do not kill, honor they father and they mother, etc. are just a nice way to live. What does an atheist have as a code of ethics? None that I know of. What a sad existence and then to believe that there is nothing beyond death, period, how sad.

Who shall ever believer in him shall not perish, but have eternal life.

Again, I feel sorry. Must be a pretty hollow life.

Atheism isn't, strictly, the belief that there is no god; rather, it's a lack of belief in gods, and as such it can legitimately overlap with agnosticism, or it can cover belief in a godless universe, or a sort of apathy toward the whole topic.

It's also a much-abused term, as you'll see if you hang around this site for more than five minutes.

Personally, I'm an "anti-theist" - I believe not only that there is no god, but that the world's monotheistic religious traditions are viral and ultimately harmful. But that's not atheism per se; it's a more extreme and specific position.

Saying atheism to be a belief is similar to claiming Not collecting stamps to be a hobby, which is ridiculous. Atheism is simply a lack of belief.

Because theists are a clear majority in the world, theism is implicitly assumed to be the default spiritual stance and hence atheism is considered to be a belief.

If we had a lot of doctrine, it wouldn't be atheism.

We don't all hang out on Sunday, formalizing our beliefs and concepts. We just don't believe in God. Try this one instead, see if it explains any better:

What is the concept of not believing in unicorns? Is it a concept, doctrine or belief? How do you practice your disbelief of unicorns?

Most self-labeled atheists seem very insistent about their label. It does not seem reasonable to me that anyone would be so adamant about a lack of belief. Thus, I regard atheism as a belief. It is the belief that there is no God.

In a technical sense, the word "atheist" might mean merely "not a theist", but in actual usage, as applied by atheists to themselves, the word clearly seems to mean something more. People don't defend a lack of belief with the vigor atheists defend their position of atheism. Atheists seem very sure about the matter, sure that there is no God. That's a belief.

As for how atheism is practiced, there is much variety. Some atheists live with no apparent significant regard for matters of religion. They pay religion no attention, give it no particular thought. Other atheists pay a great deal of attention to religion. They seem very clearly to hate religion and all practitioners of any religion. Some atheists are very aggressive about eliminating religion from public life. Such extremism is most evident in atheist governments like the former Soviet Union and current communist China. Most atheists are not actively hostile towards religion, but surely for some atheists, religion is very important. They engage it with hostility whenever possible.

I am Roman Catholic.

Peace be with you.

EDIT: A simple reading of some other answers here makes it very clear that some atheists are very hostile toward religion and religious people. Accusations by innuendo or otherwise that atheists are distinguished by their tendency to use their brains is a typical example of a hostile atheist, the innuendo being that religious people are a bunch of idiots.

EDIT

EDIT: Apparently schools, colleges, universities, hospitals, homeless shelters, food pantries and "soup kitchens" for the poor and hungry are bad things in the minds of some atheists. How else could they be so hostile to organizations like The Catholic Church, which invented the university system, and educates, feeds, shelters and cares for hundreds of millions of people every day.

Atheism is simply the absence of belief in a deity. There's no concept of the absence of something. Like the other poster stated, to be an atheist all you have to do is not practice theism.

There is no concept, only the lack of belief in deity, and usually the total absence of all superstition.

A non-astrologer is someone who does not believe in astrology. A bunny-hater is someone who doesn't believe the Easter Bunny. An atheist is someone who doesn't believe religions are true.

At first finding out the Easter Bunny wasn't real really depressed me. The Easter Bunny used to give my life a lot of meaning. I got used to the fact that the Easter Bunny wasn't real, and tried to make the best of my situation.

That's how rabbitophobia (disbelief in the Easter Bunny) is practiced. I imagine atheism is practiced the same way.

For the atheist there is nothing like the imaginary thing so called religious people call God. That is all. They do not go to chrch, temple or mosque. Otherwise they are normal people with similar emotions as any believer has.