I tend to talk here as if there is only one kind of agnosticism, the kind that I myself subscribe to. In fact, there are rather a lot of them, but the vast majority can be classified into two major types. In theological circles, my agnosticism is of the type generally referred to as ‘soft’ or ‘weak’ agnosticism. It’s the idea that we do not currently know whether or not there is a god (or goddess, or pantheon, etc, etc).
The other kind of agnosticism is called ‘hard’ or ‘strong’ agnosticism, and is the idea that we cannot know whether or not there is a god. (As an aside, these terms in their own way illustrate the absolute premium that Western society places on decisiveness and certainty – at least the ‘strong’ agnostic is certain, dammit!)