An agnostic is a doubter. Agnostic, when used as an adjective, means doubting. Someone who is an agnostic on the subject of God may doubt any or all of the myriad definitions or descriptions of God that have been put forth since the human mind began to grapple with the puzzle of existence. An agnostic may doubt the claims made on behalf of a god or gods, such as “God created the world” or “God has a special interest in my day-to-day well-being.” He may doubt such statements out of mere spite or perverseness, but ideally he will base his doubt on evidence, or the lack of it.
An agnostic is not quite an atheist. The atheist believes in the negation of what the believer believes. He repudiates the idea of God, so for him all claims presupposing the existence of God are untrue or nonsensical. It isn’t accurate to say that an atheist is a nonbeliever; you have to say that he believes in something which is the denial of what the believer believes, for without the idea of God there would be no atheists. You could also say that the atheist is just as credulous as the believer.
Thus, it follows that the agnostic may doubt both what the believer believes and what the atheist believes, with perfect consistency. Just as the claims of believers can be doubted for insufficient evidence, so can the counter-claims of atheists, on the same basis.
The atheist will object, and say that the burden of proof falls on the believer. Using the analogy of a criminal trial, he may liken the believer to a prosecuting attorney, who must marshal his evidence to prove his case against the defendant. This is fair enough, but it’s also accurate to say that in a court trial the task of the defending party is to disprove the purported evidence in order to prove innocence.
The weakness of the argument is plain: in a trial, the combatants deal with facts, but in an argument between believer and atheist, both sides traffic in conjecture. All arguments about God, on whatever side, are simply guesses. Belief, no matter how fervent, doesn’t constitute truth.
This being the case, the agnostic is as entitled to his doubt—that is to say, to his refusal to guess—as the believers on both sides are entitled to their beliefs.