> In the sciences, "someone says" is the lowest form of evidence there is.

Actually, it really depends on: - who says it - is the statement within their field of expertise - do they have known or likely personal incentives - does the topic carry significant political, religious or ideological implications - is the topic politicized - is the field itself heavily ideological or activism oriented, hard science or somewhere in the middle - is the statement consistent with statements from most other trusted experts