Typically, Scripturalists take the position that the Bible is the only source of knowledge. All other sources of information are relegated to opinion. But there's a basic problem with that: knowledge of the Bible depends on memory, and memory is fallible. So the logic of Scripturalism commits the typical Scripturalist to the position that Christians can't know anything at all. They can't know what they Bible says because their knowledge of infallible Scripture is only as good as their fallible recollection of Scripture. But in that event, their knowledge of Scripture falls short of true knowledge, as conventionally defined by Scripturalism.