Like pretty much every other philosophical definition ever invented, agnosticism has also been split into so-called "weak" and "strong" positions.<quoted text>
agnostic is someone who neither believes nor disbelieves in the existence of a deity or deities, whereas a theist and an atheist believe and disbelieve, respectively.
 Strong agnosticismGoing by several titles, including "strong," "hard," "closed" and "permanent," strong agnosticism states that there is no way to answer the question "does God exist?" and further that that, there never will be. It's kind of ironic that something developed to avoid a faith position would state such a thing as a clarifying remark, as should it turn out to be wrong there would have to be some serious goalpost moving to be done! This is similar the belief held by most people who think science should keep it's filthy nose out of religious matters.
 Weak agnosticismThat strong agnosticism also goes by the name "permanent" this should be a clue as to what the weak form is; that is, in principle, the question of God's existence is solvable and evidence can be sought. While this isn't synonymous with God's existence definitely being knowable, it has an open mind as to whether we could figure it out. This is almost like being agnostic about being agnostic.