I guess I didn't make myself clear. Let me try to fill in some holes.
***I find it ironic that you don't know if ignorance exists or not. Maybe I'm missing something? ***
I don't think there is any irony here. The important claim I make is that I know virtually nothing. Whether ignorance exists or not is simply one example of the many things I don't know.
In my post, I did not intend to discuss any possible basis for knowing whether or not ignorance exists. Instead, I was trying to describe a basis for doubt. It seems to me that if you can find some reason for doubt, then you have indirectly shown that you don't know. That was my intended approach.
***In all honesty I don't know what "forgotten" means.***
That's the spirit. I don't know either. Another example.
***I have no idea why some information is readily available to me and some isn't.***
Maybe you don't. But I am pretty sure you have the capability of coming up with such an idea. And maybe this can help illustrate my point.
It is easy to find things we don't know, i.e. things we can't explain. It is also pretty easy to come up with some explanation as long as the explanation doesn't have to be believable. It is also possible, in some cases, to come up with a believable explanation even though there may be no basis at all for knowing the explanation is accurate.
An example of what I mean by that last statement would be that if you found a tennis ball in a ditch, you could come up with the explanation that someone threw it for their dog to fetch, and the dog couldn't find it. That is a believable explanation. But, in the absence of other information, there is no basis for believing that is what actually happened.
What is believable to one person may not be believable to another person. (e.g. the difference in the existence of Sasquatch between me and Luis.) That is why I think it is so useful to consider beliefs to be identified with a point on a numeric scale from 0 to 1 indicating the level of confidence one has in the belief.
Now, let's go back and examine the question of "why some information is readily available to [you] and some isn't". You said you have no idea, so let me propose one. This will, of course, be pure idle and wild speculation, and I make no claim about its truth. It will also fall somewhere on your believability scale that may be different from where it falls on my believability scale. But the only objective I have is to get you to agree that it is possible to come up with some idea, maybe not necessarily the one I am proposing, that if true, would provide a believable answer to your question.
So here is a possible explanation: Suppose that there is a relationship between life and death that is analogous to the relationship between sleeping and waking, sort of the reverse of what Hamlet suggested. Then, to die would not be to "sleep, perchance to dream", but to wake and to find out that life was a dream. If this were the case, it wouldn't be much of a stretch to suppose that upon such an "awakening", we might remember that we indeed know everything. Or at least, a bunch of things that we didn't "know" before we died.
Now, whether that is believable to you or not, is not important. I simply used that as an example of my train of thought to illustrate what I am getting at. I maintain that if you can imagine any explanation which explains the non-existence of ignorance and which makes sense to you, (i.e. it is believable to you -- and again, I don't mean believed by you) then this imaginary explanation forms a valid basis for doubt that ignorance exists.
In this way, I think one can come up with a valid reason to doubt virtually all assertions (again with the exception of "thought happens".)
Now, this doubt may be miniscule and not a basis for belief at all, but nonetheless, I think it is non-zero.
Now, along these same lines, I think that about 463 angels can dance on the head of a pin.