Earlier quoted context omitted.
Max Planck: people have confirmation bias You: but he's a physicist, in biology things are harder to prove (the point is that people have confirmation bias even when things are 'easier' to prove)
Aren't they?
People have confirmation bias regardless of being shown evidence, it's the central feature of confirmation bias that you interpret new information in a way that supports your pre-existing view. It's a human trait not a feature of the subject matter.