jayjay
You simply evaluate it like any other evidence. The method of transmission may cause you to give less weight to the evidence, but it remains evidence nonetheless. Standing alone, the new testament is not less reliable than Tacitus. You may find that other evidence weighs against assigning a high truth value to the events described in the bible, but that question is logically distinct from the question of whether the bible is itself evidence.
Well, let’s take the easy one. Break this down into its several propositions and assign them relative truth values. Work with me here.
Prop 1) The new testament is correct. Jesus was god and the miracles really did happen. There is some evidence for this, i.e, the new testament itself. However, there is lots of countervailing evidence for this, too. Eyewitness accounts can be flawed, the events may have been mistranslated, what we know of the physical universe makes these events improbable, etc., etc.
Prop. 2) There is a universal supreme being but he/she/it has got nothing to do with the bible or any other world religion. However unlikely you may find proposition one, this proposition is even more unlikely since it must be weighed against all the counter evidence tending against proposition one but has no emperical evidence of any sort, not even the transmitted eyewitness accounts of the bible, to support it.
So Prop 1 has a relatively higher truth value than Prop 2.
Now consider the following propositions
Prop 3) God can manifest himself any way he likes
Prop 4) God has manifested himself as Justin Timberlake.
Assuming, for the puposes of this argument that there is a God, Prop 3 has a high truth value. If there is a God, he can show up in a cloud of fire or whatever.
Assuming there is a God, however, Prop 4 has a low truth value. First, just in general, under proposition 2, there is no particular reason to believe that god happens to be manifesting on earth at the moment or that he would ever bother to do so. Thus, assuming prop 2, prop 4 is always relatively unlikely at any particular point in time.
Assuming Prop 1 is correct, Justin doesn’t fit the bill. He doesn’t conform to the description in the new testament. There is some probability, of course, that everything in the new testament is correct except for the bits about the second coming. But we can see that that has a relatively lower truth value than the whole thing being correct. If the bible is correct and if it has been miraculously preserved, it is relatively unlikely that god futzed up one bit of it while leaving the rest intact.
We also have additional evidence about Justin Timberlake in particular. He hasn’t done anything particularly god-like. In fact, he’s done a lot of stuff that would not be god-like by anyone’s definition. This is evidence suggesting that Justin Timberlake is unlikely to be God.
This raises an interesting, yet obvious point. The truth value of the statement “God is physically incarnated on earth right now” always has a higher truth value than “X, who is currently on earth, is God.”
So now we can re-assemble our statements and assign them relative truth values.
God will return at some future date in flames in the sky. Assuming there is a god (which both statements do) God can return any way he likes. There is some evidence that he has said that this is the way he will return. Moreover, and more critically, there is an infinite, or at least extremely large period of time for this event to occur. In other words, the low probability of this happening at any given time must be integrated over a long period of time in order to arrive at the true probability of this ever occuring.
God has returned as Justin Timberlake. Being all powerful, etc., God could return as Justin Timberlake. However, there is no evidence that God has said he will return as Justin Timberlake. Justin Timberlake has done nothing god-like. In addition, it is simply generally unlikely that god happens to be manifesting just now.
We can therefore conclude that it is relatively more likely that god will return in a dramatic fashion per the new testament than as a member of a boy band.