Another good example, 620 nm, is that red or orange light?
I can go to a psychiatrist and persuade him/her that I have a bipolar disorder. Or that I'm schizophrenic, or depressive. And that's because there is no way for psychiatrists to know. You can talk all day long about all types of brain imaging tests that could reveal the diseases. But if that in fact was true then psychiatry would use the tools in the diagnostic process. If nothing else then at least to shut up guys like me who laugh at that "science".
Do you think that I can't go to 3 doctors and persuade each of them that I have a psychiatric condition and that they wouldn't give me a diagnosis?