Am I correct then if I asume that I have to read it and interpret it in order to measure doctrine against it in cases when doctrine claims scriptural basis? But that's the least of my problems with Sola Scriptura. I assume that Sola Scriptura rejects doctrines that can't claim direct basis in scriptura (correct me if I'm wrong). These cases, when doctrine can't claim direct scriptural basis and is in the same time not obviously contrary the scripture, are the most problematic. Sola Scriptura would discard such doctrines as unscriptural and say "Its existence can't be proven so we reject it"...and in doing so would commit itself to exactly the same logic those who reject existence of God most oftenly use - "Its existence can't be proven by means we accept so we reject it". In both cases the decision to reject is based on a logical fallacy know as "Absence of evidence". It's amplified by narrowing the field of valid proof to the contrary, meaning - accepting only scripture, or accepting only evidence in confinements of scientific method. The problem wouldn't exist if proponents of Sola Scriptura would simply say - we don't know, maybe it's valid maybe not, but it doesn't fit into what we accept as proveable. Not to mention that, in my opinion, if all implications are to be observed, it potentialy limits God.