I'll let the theists speak for themselves: Faith is belief in things unseen. In other words, beleif in the absence of evidence, or in contradiction of the evidence.
Though really in my mind faith isn't about the evidence at all--it's about the conclusion, and the evidence is considered irrelevant to that conclusion. If a person has faith that, say, Jesus existed the evidence truly doesn't matter one way or another. The conclusion wasn't arived at via evidence, and while the theist will gladly use any evidence they find to persuade others their own belief is not influenced by it one way or another.
Deluge Geology is another great example. People come at this from exactly the wrong perspective from a scientific perspective: They arive at the conclusion that there was a great Flood prior to looking at the evidence, and in truth (despite what Creationists claim) the evidence is irrelevant to their arguments. You can see that in the fact that no Deluge Geology advocate provides examples of flood stratigraphy (there are many, many, many examples in geology--it's a rather common topic in sedimentology lectures, as they are specific, definite events on a human scale and therefore easy to analyze). However, show a hammer that's been mineralized by solute-rich groundwater and they'll present that as evidence for rapid fossilization. The evidence is irrelevant; at best it's window dressing, at worst it's ignored. They've already come to their conclusion.
So I think discussing criteria for accepting a concept and faith as two different aspects of the same concept is incorrect. Once you agree that there should be a certain criteria for accepting a concept (theory, hypothesis, argument, what have you) you've accepted that the proper mode of thinking is that the conclusion should be based on the evidence. Faith rejects that mode of thinking. These aren't two different points on the same graduated scale, but rather two different scales orthogonal to one another.
Hmm.
Well, I actually do use the word faith in a non-religious way. The wiki definition is good enough I suppose:
Faith is the confident belief or trust in the truth or trustworthiness of a person, concept or thing.
I
think you're using the term "faith" more akin to the biblical definition of faith: the substance of things hoped for and things unseen.
Because by the wiki definition of faith, I could say that defining knowledge as 95% certainty is synonymous with having faith.
Now ... further clarifying this: I come from no religious upbringing, so it's hard for me to view the term "faith" as being exclusive to religious constructs. If I get into a plane to fly from New York to London, I have "faith" it will arrive there safely. If I wanted to break this down further ... my faith rests on the previous successful flights I've been on, the small amount of annual crashes with whatever company I'm flying with, etc and so forth. But there is that uncertainty that two missing rivots later will spell my demise lol. Nevertheless, it's faith in my eyes. If I didn't have it, I wouldn't get on that flight. Or in that car. Or marry that person. Or take that pill. Or believe my teacher. Or reach out to pet that dog. Etc and so forth.
Now, all of this is backed by "evidence" of some kind. None of the evidence is "proof" until events unfold. It's merely building up a statistical probability that what I'm trusting as knowledge to be sound and trustworthy. Say, 95%. In this sense, I still see faith as being synonymous with knowledge.
Now, the way you are describing faith, seems to be the type that is exclusive to a certain kind perhaps? Where the probability doesn't even fall within a percentage. It is outside of the 0 and 100% range lol. There is no 1% possibility or 99% possibility. There isn't even a 0%. There is no evidence whatsoever for the focus of the faith: it's completely IMAGINARY. The only place it exists, is within the human mind in the form of imagination. Thus, the person has faith in their imagination. This would border into delusion, which is also distinct from basing a perception on false or incomplete information.
Which leads to another point (just to toss an extra two cents in there). Arguably, many religious ideas come from archetypes, and are based on incomplete information. I don't know of any mainstream religions that will acknowledge their beliefs spur only from imagination as the sole source. Therefore, the "evidence" for the religion (like the personnage of Jesus) might be evidence of SOMETHING .... an original person who did exist, or someone who did create something from imagination, or an actual event. This is why I am a proponent for anecdotes being a form of evidence ... they are not definitive proof, but they might allude to something real. "I saw a UFO fly over my ranch" was really a sun-dog in the sky, for example. The anecdotal account is evidence there might be something the person saw ... and without definitive proof of ET's perhaps the most logical explanation would be a sun-dog and not aliens. Nevertheless, the might not even be definitive proof that it was a sun dog if no one can produce pictures of the event that weren't faked ...
But anyway I'm chasing a rabbit hole. The point, is that by your comment about knowledge, I saw no difference between that definition and one essentially synonymous with faith.
Now, one thing I've noticed ... is that "faith" is almost always viewed as a "bad word" around here. It's something I've never understood unless it's because it's so entrenched with religion that it's impossible to detach it from religious speech. Every now and then when I use the word, I don't understand why the convesation always has to go directly to religion and not remain in the realm of "neutral semantics" or philosophical ideas. I have no desire to defend any religion .... but faith is seemingly something we all live by, everyday, on some level. Otherwise we would never leave our padded cells lol. To me, if someone says, "I have no faith in anything," then that means that they definitively know all knowledge perfectly at all points relative to them at any given moment (i.e. they are individually perfect), or they are completely and utterly random in their response to reality with no coherence to anything in particular. IOW, being correct or incorrect is irrelevant across the board.
Can I ask you .... do you have a personal aversion to the word, or would you use it to describe yourself if the word could be "salvaged" amongst the skeptics? lol. I almost want to open a thread on this question ....