What types of counter-evidence would call Shaffers thesis into question?

Counter-evidence that could call Shaffer's thesis into question would include historical records or archaeological findings that support a different origin story for the alphabet, such as a single inventor or a different geographical region where writing systems originated. Additionally, evidence of earlier or contemporary writing systems that predate the Phoenician alphabet could challenge Shaffer's claim of its innovative and influential nature. Moreover, linguistic or comparative studies showing significant differences or lack of connection between the Phoenician alphabet and other writing systems might also cast doubt on Shaffer's thesis.