marwen,
Well, I hope Trumble doesn't mind if I steal some thunder, but one point I always find important in discussions about proof is whether you're talking about absolute proof or using proof in a colloquial sense meaning 'provide evidence for'. In the colloquial sense, science provides 'proof' for a Theory every time it discovers a new fact that fits that Theory. But in the absolute sense no Theory can be 'proven' because it is impossible to know whether you've discovered every single possible fact in the Universe relevant to the Theory in question - there could always be another facet of reality out there waiting to be discovered that doesn't fit. Now, I'm not sure in which sense you're using the term 'proven' because you also mention logical and mathematical proofs, which use the term in its absolute sense.
But, even in the colloquial sense of the term, if you come across a fact that doesn't fit a Theory then you know the Theory is incomplete - even if you don't have absolute knowledge of all possible facts. That's why it is usually said that Theories cannot be (absolutely) proven, yet they can be (absolutely) disproven.
So, in an absolute sense, science can never be sure if it's correct. Thus, it could be termed 'fiction', but only if you redefine fiction to mean everything that isn't absolutely correct - in which case almost all court verdicts could be described as 'fictions' too due to the lack of absolute evidence. More usefully, science can be seen as a methodology that constantly spirals inwards, closer and closer towards the absolute truth. Whether it's ever actually possible to obtain absolute truth will probably only be known if we ever get there.
Which leads back to the subject of this thread. Most theists proclaim that they 'know' the 'absolute' truth. From a rational perspective, as that described for science, above, the corollary of this statement is that someone who knows the absolute truth must be aware of every possible fact in the Universe. If they don't, then there is no way for them to be sure that there aren't facts that can be found that would disagree with the 'absolute' truth they are proposing. How, then, is it possible to claim to know absolute truth?
One way religion tries to claim this is by simultaneously claiming the absolute truth, while claiming that the absolute truth is 'unknowable' - if something is 'unknowable' then no observed fact could ever be used to demonstrate that it isn't the absolute truth. How many times has it been asserted on this board that God or Islam is the absolute/ultimate truth yet that God is beyond our capacity to understand? These two claims are mutually exclusive in an epistemological sense: how is it possible to claim that something that cannot be understood is the absolute truth? By definition, you cannot come to any absolute conclusions to things that are even partially, let alone completely incomprehensible. The religious 'answer' to this inherent irrationality is to 'have faith', or, in other words, to ignore the inherent contradiction and accept the assertion with no qualification - but this provides no satisfactory, rational solution (although it may be a very appealing emotional solution).
I would like to see if this contradiction can be resolved, but I haven't found a solution yet in any of the religious writings I've been over that make these claims.