I still don't understand. What difference do you make between "absolute truth" and "one absolute truth"?
Do you know the difference between absolute knowledge and knowing one thing?
You don't say where you got this idea of absolute knowledge but you should be aware that there are different notions of absolute knowledge. One is from Hegel for example, where absolute knowledge is "knowledge in the form of the complete self-consciousness and self-possession of spirit" and so really has nothing to do with what you seem to be referring to.
Another is from Kant (see for example
http://www.philosophy-dictionary.org/ABSOLUTE):
Kant refers to absolute reality and knowledge, in contrast with empirical reality and empirical knowledge. To say that space and time are transcendentally ideal is to deny that they have absolute reality. To have absolute knowledge would be to know something about a thing in itself, not an appearance or object of sensible intuition.
Again, nothing to do with what you say.
There is also Husserl, (see for example
http://en.wikipedia.org/wiki/The_Phenomenology_of_Spirit), for whom absolute knowledge is knowledge regarded as fundamental to reality. Again nothing so specific as what you suggest here.
And the same is obvioulsy true of the notion of absolute truth.
It is the same difference.
Absolute truth is all possible truth. If all I have is one truth I never know for certain it is the whole truth. I never know for certain it is absolute. It could be part of some trick.
Ok, it's what you mean by absolute truth but you give no source. You should be aware that your sense isn't at all the usual sense. It may be the sense used by some people but you would need to really start by specifying first what you mean by it.
The only way to have certainty is to have all truths, ultimate truth.
That's your opinion but that not the usual meaning of absolute knowledge or absolute truth.
More importantly, I think you are probably confusing the usual concept of absolute knowledge, which I believe would be knowledge of something fundamental to reality, whatever that may mean, with some argument concocted by some Super Bright mind to the effect that, as you just explained here, no knowledge is possible without having all knowledge. That's an interesting idea. I know it to be false though. However, even without me saying anything about that, you should realise that you would need to prove what you say. The usual argument, that if you don't know absolutely everything of reality then you may be mistaken about what you think you know doesn't in fact apply to all knowledge. In effect, if you do know something, without knowing everything, then nothing that you don't know could possibly change the fact that you know this something, and that's a consequence of what we mean by "knowledge". So in effect, you are merely assuming first that you don't know if you know something. But, if you knew that you know something then you would know that your argument does not hold water. That being said, I in fact accept a restriction of your argument to a certain kind of knowledge, where in this case it is obviously true, at least as far as we know now.
Finally, given how
none explained what he meant, it is no apparent to me that you two are really talking about the same kind of "absolute truth". So you may need to revisit that assumption as well.
EB