There were lots of things that Jesus is recorded as saying or doing when the disciples were not around, or when no one was around. When I say the Gospels are based on eyewitness accounts. I am not saying that someone was there, in the moment, journaling everything that was happening. It is quite likely that Jesus related what happened to him in the wilderness as a teaching to his disciples about dealing with temptation.
It is not farfetched at all that Jesus recalled to them events that happened to him or that someone else did the same.
So the Bible's inclusion of things Jesus said and done when others were not present is not problematic, nor does it serve as an adequate claim for mythology of Jesus as depicted in the Bible.
It seems we have slightly different definitions of "far fetched" when it comes to stories about people being teleported around by the devil himself.
But I fear we have an even more basic misunderstanding here:
I am not in any way claiming that such stories are in any way a proof or "adequate claim" for mythology of Jesus... all I am saying is that such stories allow for the option of the myth variant.
The main argument that many Christian apologets present for the "historic" Jesus is "the authors wouldn't have made it up".
It is quite easy to see - even without direct examples where even Christians would claim that the authors made it up - that this is a claim beyond human nature.
That's not a very good comparison. No one is claiming that Mohammed was a mythological person.
Again, you do not seem to have understood the specific distinction that I made regarding the - let's say: levels - of "mythology" in a person.
I try again: what does it mean for a "person" to be historic or mythological? How much of what is told about him can be false or must be true to be "historic" or "mythological"?
Another example: Socrates. (Hey, Monk Brendan: you wanted to know what I thought about the historicity of Socrates: look here!)
We know, from different sources, quite a lot about Socrates. When he was born, when he died, how he died, what family he came from, what he taught... ... but all of that is based on
stories that other people told about him. Stories that other people used as back-up for their claims.
It is very well possible that there wasn't a historical Socrates. Everything socratic can be explained - and isn't even "far fetched" - without the existence of a historic Socrates.
There might have been a historic basis for this figure. There might have been more than one. He might have been a pure fiction.
We cannot be sure... but it is very well possible, and wouldn't change basically anything about the history or developement of philosophy since.
With different persons, this is not quite the same. With Caesar or Augustus or Alexander for example. Here, the known historical facts demand the existence of a historical figure as a basis for the stories... even if not all, not even most, of what is told about them is "true".
Could the macedonic expansion and conquest of the eastern world have happened without some sort of personal driving force behind it? No. Could it have happened without this force being divine, slashing through knots and having all kinds of omens predicting his greatness? Yes.
Could the islamic rise and expansion have happened without a personal figurehead establishing and leading this new movement? No. Could it have happened without this figure talking to angels and riding into heaven? Yes.
And here's why I think the in contrast to Alexander or Muhammed, Jesus is more like Socrates.
The socratic school could have happened without there ever having been a real Socrates. And Christianity could have happened without there ever having been a real Jesus.