Why do scholars disagree about whether St. Luke wrote the Gospel According to Luke and Acts of the Apostles?

Scholars disagree about whether St. Luke authored the Gospel According to Luke and the Acts of the Apostles primarily because of discrepancies between the portrait of St. Paul the Apostle in Acts and the impression of him provided in his own letters.1

Key points of scholarly debate include:

• Theological Differences: Critics note that the theological emphases in Luke and Acts differ significantly from those found in Paul’s writings.1
• Divergent Accounts: The description of the Council of Jerusalem in Acts 15 is seen by some as inconsistent with Paul’s own account of the conference in the Letter of Paul to the Galatians.1
• The "We-Passages": While traditional views cite the first-person "we" sections in Acts as evidence that the author was a companion of Paul, some scholars argue these are merely a stylistic device common in ancient travel literature rather than proof of personal participation.12
• Historical Consistency: Some argue it is difficult to reconcile the author of Acts with a close companion of Paul, given the apparent disagreements regarding fundamental issues like the Law and Paul's apostleship.2