When people make up new isms, they really out to give them new names, to cut down on confusion.

Huxley's ism ... agnosticism ... is not about claiming something is unknown ... is totally about being completely uncertain, and incompatible with beliefs ...

"The extent of the region of the uncertain, the number of the problems the investigation of which ends in a verdict of not proven, will vary according to the knowledge and the intellectual habits of the individual Agnostic. I do not very much care to speak of anything as “unknowable.” What I am sure about is that there are many topics about which I know nothing; and which, so far as I can see, are out of reach of my faculties. But whether these things are knowable by any one else is exactly one of those matters which is beyond my knowledge, though I may have a tolerably strong opinion as to the probabilities of the case. Relatively to myself, I am quite sure that the region of uncertainty–the nebulous country in which words play the part of realities –is far more extensive than I could wish."

Apparently everything he ended up saying still leaves ambiguity, when taking into consideration the fact that people don't read everything he said.

"I trust that I have now made amends for any ambiguity, or want of fulness, in my previous exposition of that which I hold to be the essence of the Agnostic doctrine. Henceforward, I might hope to hear no more of the assertion that we are necessarily Materialists, Idealists, Atheists, Theists, or any other ists, if experience had led me to think that the proved falsity of a statement was any guarantee against its repetition. And those who appreciate the nature of our position will see, at once, that when Ecclesiasticism declares that we ought to believe this, that, and the other, and are very wicked if we don't, it is impossible for us to give any answer but this: We have not the slightest objection to believe anything you like, if you will give us good grounds for belief; but, if you cannot, we must respectfully refuse, even if that refusal should wreck morality and insure our own damnation several times over. We are quite content to leave that to the decision of the future. The course of the past has impressed us with the firm conviction that no good ever comes of falsehood, and we feel warranted in refusing even to experiment in that direction."

Re-worded: Being 1% uncertain that any god does not exist does not make a person's belief that the existence of god is unknown and probably unknowable. Agnosticism is not a measure of certainty or uncertainty. Still confused?

"Being 99% certain that any god does not exist does not make a person's belief that the existence of god is unknown and probably unknowable."

You have this precisely backwards because you're not acknowledging who's mouth the God claim originated: the theists mouth yeah? - Or have I got that wrong? This means that it's entirely the claimant's responsibility to carry the burden of proof for their claim not the people simply say 'I don't believe you.' - If you disagree tell me this: If I claim the Loch Ness Monster is real does it make sense for me to say '"Being 99% certain that any Loch Ness Monster does not exist does not make a person's belief that the existence of a monster is unknown and probably unknowable."? - Well?????

"Agnosticism is not a measure of certainty."

Agnosticism is saying 'I don't know' to claims of some god's existence - or for that matter claims of a teapot somewhere in orbit between Earth & Mars. Yes I have to say I do not know for sure whether there's a teapot there, or a monster in Loch Ness or a god. But again since I never originated any of these claims that's the wrong question. The right question to ask when people make those claims is 'Is there any good reason to believe the claim?' & the answer is 'No'. Pretending it's our job to prove to the claimant that there isn't a teapot or monster or god is simply ludicrous because that's entirely the responsibility of the person suggesting such claims are worthy of respect & no one else's ever ever ever.