Then absolutely knowing something is not certainty? I considered them pretty much the same. There seems to be a disconnect between that use of gnostic and the common use of many the word agnostic. Otherwise, agnostic and ignorant would be synonyms.
1 : a person who holds the view that any ultimate reality (as God) is unknown and probably unknowable; broadly : one who is not committed to believing in either the existence or the nonexistence of God or a god
2 : a person unwilling to commit to an opinion about something
And I think there are many agnostics that fit both definitions. But the more I read the first definition, the more problems I have with it, as I do with many definitions of the word "atheism".
By this definition, I would not consider myself an agnostic at all. I agree with the first half of the first definition, although I see that being just as irrelevant as never being able to disprove the existence of fairies or proving any number of negatives. Which loops back to my disagreement over labeling my unbelief in all sorts of crazy things with the elegant but fun word "agnostic".
: the thought and practice especially of various cults of late pre-Christian and early Christian centuries distinguished by the conviction that matter is evil and that emancipation comes through gnosis