An agnostic is someone who claims that the existence of a God or gods is unknown and unknowable. An agnostic believes man is limited to experience only, but that experience cannot include a God or gods.
Anyone who states: "I don't know if there is a God, and neither does anyone else," are making certain assumptions: If a God exists, they have not, will not, or cannot make themselves known. In doing so aren't they discounting any knowledge anyone else may have; and discounting any experience anyone else may have; and determining the knowledge or experience themselves or anyone else could have?
Questions One Might Ask an Atheist or an Agnostic:
1. "Do you know everything there is to know in the whole universe"? If their answer is "Yes" would they not be making themselves "omniscient," a quality that only a God could have?
2. "Do you know half of everything there is to know in the whole universe"?
3. "Let's pretend that you are really, really, really smart, and you actually do know half of everything there is to know in the whole universe. Could God exist in the half you don't know about yet"? If they are an honest person, at least to themselves, wouldn't they have to admit there could be a God out there that they just don't know about yet?
4. A very thought-provoking question though might be: "If a God does exist, and they made themselves known to you, would you worship that God"?
There are millions of people that believe a God does exist, and that God has made Himself known to them. To those people aren't the agnostic or atheist basically replying: "No He hasn't, and my opinion and personal experience are the only ones that matter." In science, observation and experience count more than someone's opinions.
To believe or not believe, is a choice. Everyone's reasons for making those choices may be very different, but they are choices none the less. But then again, that is just my opinion, based on my own knowledge and personal experience. What is your viewpoint?