It's Not an Argument from Reasoning

 ¹¹ Dear brothers and sisters, I want you to understand that the gospel message I preach is not based on mere human reasoning. ¹² I received my message from no human source, and no one taught me. Instead, I received it by direct revelation from Jesus Christ.

It is important that Paul establishes where his version of the gospel comes from.  Paul lets all know the gospel he preaches is really not his version at all.  he didn't learn it from his own studies, he didn't learn it from those around him, he didn't learn it from the apostles themselves.  There was no human source, not others, not even himself.

The gospel he preaches came from direct revelation from Jesus Christ.

Paul talks about how he was zealous in following the Jewish religion, but something divine happened in his life.  Gods grace exploded upon him and God revealed his Son to Paul.

For three years Paul was in Arabia, away from the influential men of the faith.

Because it was 3 years later that Paul met with Peter the statements of 1:11,12 stand strong.