Atheism is a belief, just like any theistic belief, and I humbly submit that Belief is Error.
The Atheist points to the lack of empirically defensible evidence for the existence of any supreme being, and then somehow extrapolates this lack of evidence as proof positive that no such being exists. This is not logic, unless one accepts the logic of “Humans are made of atoms, atoms cannot be seen by the naked eye, therefore humans are invisible”. The position so vigorously defended is based upon no evidence whatsoever, and thus is a belief, pure and simple. In attempts to bolster this belief, and to obfuscate their total lack of supporting evidence, the Atheist will point to a great number of scientific conclusions (which are supported by evidence) and assert that these all support his or her position since none of them have provided evidence for the existence of a Supreme being.
The Agnostic, however, faced with the lack of evidence, asserts that this shows that no evidence has been found to date, using currently available techniques. This is demonstrable, and indeed the only logical conclusion that can be drawn. The lack of evidence for a proposition is not evidence that it does not/can not exist: it simply demonstrates that evidence was not found using certain methods, and measurements. Since no realistic test has yet been devised to test for the existence of a transfinite being, there can be no evidence one way or another.
If you hire an individual to test for the levels of calcium in your drinking water, they will perform specific tests designed to demonstrate this quickly and effectively, review the evidence thus created and report to you on the results. This is the logical and scientific method, and the way of the agnostic.
If, however, this individual measured the water for cadmium, zinc and lead while considering many other factors including average rainfall and then asserted that there was absolutely no calcium in the water, based upon these irrelevant data, one might be forgiven for questioning that judgment. This is the methodology of belief, and the way of the atheist.
I think that this demonstrates clearly that Atheism is a belief, and as such cannot be supported by true logic: Agnosticism, however, accurately describes the situation: with current technology and current methodology, there is no evidence to support the existence of a supreme being, thus we cannot make any conclusions at this time.