Why did Polybius criticize the Greek historian Phylarchus?

Polybius criticized the Greek historian Phylarchus for prioritizing sensationalism over historical accuracy, a practice he deemed unprofessional and akin to the work of tragic poets.1

In his critique, Polybius argued that a historian’s primary duty is to record actual events and speeches to instruct serious students, whereas a tragic writer seeks only to thrill or charm an audience through plausible, yet potentially false, narratives. He specifically condemned Phylarchus for:1

• Attempting to astonish readers through sensationalist accounts.1
• Speculating on the probable utterances and consequences of events rather than documenting what truly occurred.1
• Confusing the purpose of history—which is to convey truth for the benefit of the student—with the purpose of tragedy, which is to beguile the spectator.1

For Polybius, history was pragmatikē historia (pragmatic history), which required an austere focus on political and military facts rather than the emotional manipulation found in the works of his predecessors.1