I know, I know. The title is a bit misleading.
But lately, I've been seeing a growing trend of digging an imaginary trench between so-called atheists and so-called agnostics. What many people don't realize is that more often than not, they are one and the same.
We need to define both terms first. Theism and atheism are about belief vs. non-belief. Non-belief in a deity does not imply a belief in the non-existence of said deity. Atheism is a response to the claim, "There is a god." If you accept and agree with that claim, you are a theist. Anything else means you're an atheist. Whether you simply refuse to believe in a deity, or actively believe no such deity exists, you are an atheist.
Gnosticism and agnosticism refer to knowledge. If you know for certain one way or the other, you are gnostic. If you don't claim to know, and make no assertion whatsoever, you are an agnostic.
Think of [a]theism and [a]gnosticism as two axes on a two-dimensional chart. The X axis would be gnosticism (0 for agnostic, 1 for gnostic), and the Y axis would be theism (0 for atheistic, 1 for theistic). Based on these two interconnecting terms, people generally fall into any one of four categories, as shown to the right.
Let's say there's a seemingly empty box in the middle of a room. A theist comes up and says, "There is an object in this box. We cannot perceive it with our senses, but I believe it to be there." An atheist would respond with, "I don't believe your claim." An agnostic atheist would respond, "I don't believe your claim, but I can't say for certain that the box is completely devoid of such an object." A gnostic atheist, on the other hand, would respond, "I don't believe your claim. In fact, I'm certain there is nothing in that box anywhere close to what you claim."
Some might say that gnostic atheism is a foolish position: that without any evidence of your own, you shouldn't make the assertion that no gods exist. On the other hand, I think it is a rather logical conclusion that one can make from the lack of evidence for a god — that because it is impossible to show evidence of a god whose properties we do not or cannot know, it is therefore logical to conclude that no such god exists.
With the release of Stephen Hawking's newest book, The Grand Design, it is even more logical to come to a gnostic conclusion of the non-existence of a god. In this book, Hawking goes into detail about his conclusion that a god is not required for the Big Bang theory, or for the universe as a whole to have come into existence. Perhaps Hawking could be described as a gnostic atheist; if so, is it really that foolish a position to have?
Some claim that "belief/non-belief" is a false dichotomy, but this is not so. You either believe a claim, or you don't. If I told you that I had magical powers and could fly, but could only do it when I was alone, would you believe that claim? If you trust that I am telling you the truth and believe what I'm saying, that's one position. The other position is that you do not believe me. That position itself is divided into two possibilities: you don't believe me, but can't say for sure that I'm lying; or you don't believe me, and claim that I'm a liar and have no such abilities whatsoever. Since it has never been demonstrated that a human being can fly without external aide, one can safely claim to know that I am lying.
Another way to put it is that the claim, "God exists," has two possible states: true and not true. "Not true" is not the same thing as "false", however. Take, for instance, the statement, "This statement is false." Is that statement true or false? It is neither, because it is a paradoxical statement. However, you cannot say that the statement is true. Therefore, it is not true. Under the "not true" category, there's "false", "paradox", "self-contradicting", and other answers that are anything other than "true".
Therefore, atheism is not about labeling the "God exists" claim as false, but about labeling it as not true. Gnostic atheists go a step further and label it false, while agnostic atheists simply say it is not true, or unfalsifiable, a sort of limbo state where the claim is not true, but cannot be proven to be false.
It's a lot for some people to wrap their head around, but this is essentially what [a]theism and [a]gnosticism are all about.