A huge amount of time gets wasted in this forum on arguments between people who are using different definitions of the terms “atheism” and “agnosticism”. This post is an attempt to end (or at least reduce) such pointless discussion by clarifying the standard definitions of those terms.
“Agnostic” is probably one of the most badly misunderstood terms in religious philosophy. Most people believe “agnostic” to mean a person who is undecided, but that’s not the formal definition of agnosticism as used by religious philosophers. The formal, academic definition of agnosticism is the belief that it is impossible for people to know whether or not a god exists, and that any attempt to discern the existence of god is therefore futile. This is not the same as someone who simply hasn’t made up their mind on the issue. Here are some links to references on agnosticism:
http://en.wikipedia.org/wiki/Agnosticism
http://www.newadvent.org/cathen/01215c.htm
There are two type of atheism: “strong atheism” and “weak atheism”. A strong atheist believes that no gods exist, while a weak atheist merely does not believe in any particular gods. Although it might seem like needless semantics, there is actually an important difference between “does not believe that gods exist” and “believes that no gods exist.” When saying “I believe that no gods exist” one is making a positive statement of belief. In other words, a strong atheist believes that he has found some sort of evidence (through logic, empiricism, or whatever) that indicates that gods do not exist. It is reasonable to ask a strong atheist for their evidence that no gods exist, and the burden of proof is on the strong atheist to back up their claim.
A weak atheist, on the other hand, is simply a person who is not convinced that gods exist. They have no burden of proof, because they are not making any claims – they are simply stating a lack of belief due to insufficient/lacking evidence. Unlike a positive atheist, it is
not reasonable to ask a weak atheist to prove that god does not exist, because a weak atheist does not claim to have such proof; rather, the burden of roof is on the person who claims that gods exist.
Note that agnosticism and atheism are not mutually exclusive; a person could be both agnostic and a weak atheist. Also, it’s possible for a person to be a weak atheist and/or agnostic in general, but still strongly disbelieve in any particular religion.
Note that I am talking about the formal, academic definitions of agnosticism and atheism here. You are certainly free to substitute your own personal definitions, but in order to avoid pointless semantic arguments you should be sure to make it clear that you are using a non-standard definition. Also, you shouldn’t be surprised if most of the other people on the board aren’t interested in your personal definition and prefer to use the standard academic definitions.