I think that the majority of problems people have regarding religion, matters of faith, and scientific understanding is a matter of language. It is in the realm of colloquial, idiomatic speech that the confused person is trapped. Some people just don’t know how we know things.
How Do You Know?
There are ways we humans have of understanding fact from fiction. We realize that we can create practically anything in our imaginations, and we know that our senses can be fooled. So we need a way to distinguish reality from pretend. We have these reliable methods (we know they're reliable because we can show them to be so).
Logical reasoning is the primary foundation upon which we build our understanding of reality. We can prove the rules of logic are true, and we therefore make them rules.
Science makes use of logical reasoning, in conjunction with:
- independent verification, to avoid group-think
- repeated testing, for consistency
- falsification, to demonstrate that a hypothesis is reliable and is not producing an incidental result
- and, most importantly, peer review, because we are all fallible. Your work is reviewed by other experts to make sure that your test methodologies are correct, that you properly falsified your hypothesis, and that your tests and results are replicable.
The problem is that the average person uses the word "theory" to mean a guess or a hunch. While I fail at times, (or I'm forced by language, i.e. "conspiracy theory",) I've resolved to use the term "theory" in scientific terms only, and when I mean "guess", I'll say "guess", or "hypothesis". But the average person will use the term loosely, and those who don’t understand the difference in terminology will get confused when they hear something like “the theory of evolution”.
What Do You Know?
Another general mistake is in the use of the term, "agnostic". When I ask someone whether they believe in god or not, some will say "I'm agnostic". Those who understand the term will realize that the answer given doesn't fit the question; it answers something else entirely. I've demonstrated the differences several times, so I won't go into it further.
The main focus here is that many people get tripped up in what it means to know something, and knowledge--or lack thereof--informs belief. The two aren't the same, but they are tied together.
So, what does it mean to know something? Or, more to the point, how can you truly be an Agnostic?
Well, it depends on what you mean by "knowledge". I’ve show above how we can know reality. If it can be demonstrated that, for example, a thing exists or occurs, and that this can be demonstrated to an incredibly high degree of predictability, then we can comfortably say we “know” it.
When it comes to believing in that thing, you still have options even if the thing can be known or not. Theism and Atheism address what you believe, Gnosticism and Agnosticism address what you know, or claim to know. If you want to define knowledge as "absolute certainty", then I’m an Agnostic Atheist; I don’t know that a god does not exist to an absolute certainty.
I don’t like "absolute certainty"; I think it’s a red herring. We can’t know anything to an absolute certainty. But if you want to define knowledge in practical terms--the way we use it in everyday language where we talk about something to some degree of certainty--if it’s okay to say "I know there’s no such thing as leprechauns", if that qualifies as "knowledge", then an I’m a Gnostic Atheist. In the same sense that I know there’s no leprechauns, I know there’s no god.
Belief vs. Knowledge, Redux
So why all this talk over belief? I mean, isn't what someone believes their own business?
Yes it is. I don't care what anyone believes, though I'd rather they base their beliefs on demonstrable reality. As I said above, knowledge informs belief. But your actions are affected by your beliefs, and that’s what matters. You can belief whatever you want until you start to infringe on others' beliefs/health/etc. That’s the point where your beliefs won’t be tolerated.
I think it’s beneficial to a society if its beliefs and subsequent actions have a basis in what can be shown to be true, and I hope that Earth’s population reaches this level ASAP.