Is the Bible authoritative or not? Bruxy Cavey has argued as follows (see here):
(1) All authority has been given to Jesus (Mt 28:18).
(2) No authority has been given to the Bible.
That is to say, the Bible isn’t authoritative. Unfortunately, this argument is logically invalid. Here I must emphasize that this isn’t a matter of personal opinion. It is a fact – as much a fact as that 7 + 5 = 12 or that circles have no corners. Indeed, the invalidity of the argument can be demonstrated in predicate logic (see here).
If you doubt this conclusion, you might also consider this (parallel) argument, having the same logical form:
(3) All money has been given to Paul Franks.
(4) No money has been given to Rich Davis.
But how, you ask, does that follow? If all money has been given to Franks, then the only way we know that no money has been given to Davis is if we also know that Franks hasn’t given any money to Davis. But do we know that? We don’t actually — not given what we’re told in (3) and (4).
And the same thing goes for (1) and (2). To be sure, (1) is true. But unless we know that Jesus neither granted nor extended his authority to anything else (the Bible) or anyone else (his Apostles), (2) simply does not follow. You might be inclined to resist this conclusion. In that case, I think, the thing to do would be to reconsider these failed inferences [i.e., (1) → (2) and (3) → (4)] — this time using the same high standards one expects to find satisfied in any sound argument, but a fortiori in arguments designed to show that what is “God breathed” (2 Tim 3:16) is not in fact authoritative.