So Paul was clearly and unambiguously talking about “a spiritual brother” but mark decided that it would have been cooler to transform him in to a biological brother, for some strange and mysterious reason…… yea sure that seems the most plausible explanation .
You are playing coy when I believe you know full well why Mark would give Jesus a live brother. He gave Jesus a mother, father, 12 apostles, events, a last supper, a crucifixion, all earthly events where Paul just said he dies and rose. At that time many mystery religions had saviors who resurrected in the celestial realm. We domn't know if Paul was referring to a similar myth. At any rate Mark created an earthly narrative. So that is evidence as to why he would also give him a brother. It is not "mysterious".
Now I explained that the Greek word Paul uses, he also uses in Gal to mean spiritual brother. He uses it to distinguish apostolic to non-apostolic brother in the lord. So, again, and again, we cannot know which meaning Paul meant. How hard is this to get? Do we need to start bringing in Greek words? The actual word for biological brother is not used.
When you say "clearly and unambiguously" you are completely ignoring a reasonable debate?
You are making many assumptions
1 that Mark copied from Paul
which I demonstrated and gave 5 peer-reviewed papers? What do you need? More examples? Would you like 1 whole response of examples? We have excellent evidence. Why would we ignore all this evidence?
There are specific examples, thematic examples where Mark changes things that could only have originally come from Paul, and paradagmatic examples like the last supper which was Jesus saying to Paul things to tell future Christians about his body and blood and Mark changed it into an actual supper with people.
Again, you just refuse to look at examples but would rather just pretend like it's all folly and PhD historians are some sort of fools wasting time?
2 That Paul meant spiritual brother
Paul uses the Greek adelphon -A neuter term meaning brother or sister through affection rather than blood
He uses it in other places to mean brothers in the lord. So again, we cant be sure. Why is this so hard for you?
3 That Mark decided to change spiritual brother for biological brother for some unknown purpose
There are hundreds of examples.
Same reason he changes the last supper message into a actual supper with people at a table.
Same reason he took words of Clement about Jesus warning about betrayers into an actual story about Judas the betrayer.
Mark likes Pauls use of stumbling block and kingdom of God and used them often.
Mark got the idea of inventing a whole narrative sequence of Jesus emulating Moses in miraculously feeding the multitudes in the desert and crossing and manipulating the sea? Just read Paul,
1 Corinthians 10:1-4:
Likewise,
Mark 4:9-20 describes spreading the Gospel as like “sowing” seeds, exactly as Paul does (
1 Corinthians 9:11); equates evangelizing as cultivating a field, exactly as Paul does (
1 Corinthians 3:9); uses the “root” as a metaphor for one’s inner depth of commitment, exactly as Paul was believed to have (
Colossians 2:7 &
Ephesians 3:17); and uses the same words in the same metaphor of increasing one’s agricultural yield by spreading the gospel on good ground (
auxanomena, “increasing,” and
karpophorousin, “bearing fruit,” in
Colossians 1:5-10). Which is another case where “Paul” is speaking his own mind, in his own words and his own metaphor, which Mark has converted into something taught by Jesus. The author of Colossians had no idea Jesus ever could be quoted in that passage, because Jesus never said any of that. Mark invented it—using Colossians.
Anyway I am confused
Did John also copied from Mark? Was James a historical person?
Paul and people he mention are considered historical.
If you bothered to actually look at Christian scholarship they have already accepted Mark was the source:
The Synoptic Problem | Bible.org
of the synoptic gospels.
Each gospel was written to improve on the last and be the one gospel used. But John is not a synoptic gospel, written too far after and too separate from the synoptics.
Scholarship considers it unreliable to an even greater degree:
"The teachings of Jesus found in the synoptic gospels are very different from those recorded in John, and since the 19th century scholars have almost unanimously accepted that these Johannine discourses are less likely than the synoptic parables to be historical, and were likely written for theological purposes."
Just because they teach a revisionist history in church doesn't make it true. If you want to honestly debate gospel historicity you should actually study gospel historicity. If you just want to deny and think scholarship that contradicts the church doctrine are "heretics" then go ahead. You will not discover truth however.