What's the "worth" of a historian's opinion on a topic they're not specialized about?
I guess this is more a question about the field of historiology itself.
It's my understanding that professional historians are heavily specialized in one region + era, and that their most of their research are heavily focused on this topic.
In that case, does the opinion of historian on a topic they're not specialized about weighs more than that of an amateur history enthusiast? Should I consider that a historian is naturally more informed about their history-related answers in topics not their speciality, or should I take it with the same grain of salt of a non historian in this case?
Asking the question, because I was once chatting with a guy who said he was a historian specialized in Modern Greece. But while talking about Ancient Greece, he had claims that seemed to be opposite to the historians' consensus on the topic (afaik). And thus I wondered how seriously I could take his claims, being aware that he also had political biases that could influence his view.