I'd be tempted to add Gregor Mendel (whose experiments on plants and his analysis demonstrated how genes work) to that list.

It wasn't so much that the 'professional' scientists of the time considered that he was wrong - rather that they didn't even know of his results. In particular Darwin puzzled over what the mechanism for transfer of traits was and was searching for a reason why traits wouldn't be continually diluted ... which was an answer that Mendel had already answered very neatly. (Darwin argued for pangenesis as he was sure from his observations that blending inheritennce would have diluted distinct traits)

I'd argue that Mendel would meet the criteria as being a 'non-professional' as while he did teach physics - he repeatedly failed the teaching exams so he wasn't qualified to teach high school or adults - only young children. A pedant may point out that as presented his experiments in a couple of meetings and published an ignored paper he should be regarded as a 'professional scientist' .. but since he own boss in the church banned him from studying mice as it was considered wrong to study animal reproduction - I'd safely argue that it was a very non-scientific profession he was in.

I'd be tempted to add Gregor Mendel, whose experiments on plants and his analysis demonstrated how genes work, to that list.

It wasn't so much that the 'professional' scientists of the time considered that he was wrong — rather that they didn't even know of his results. In particular, Darwin puzzled over what the mechanism for transfer of traits was and was searching for a reason why traits wouldn't be continually diluted — which was an answer that Mendel had already answered very neatly. (Darwin argued for pangenesis as he was sure from his observations that blending inheritance would have diluted distinct traits.)

I'd argue that Mendel would meet the criteria as being a 'non-professional' as while he did teach physics — he repeatedly failed the teaching exams so he wasn't qualified to teach high school or adults - only young children. A pedant may point out that as presented his experiments in a couple of meetings and published an ignored paper he should be regarded as a 'professional scientist', but since his own boss in the church banned him from studying mice as it was considered wrong to study animal reproduction — I'd safely argue that it was a very non-scientific profession he was in.