I think that when evaluating an item, one has to keep somewhat an open mind and naturally use known comparable items, and consider viable reasons for any deviation or variation in its character. In addition to visual comparisons which correspond to provenanced examples or otherwise detailed support, there has to be physical or 'forensic' examination.
We cannot (in my opinion) disclaim an item or elements of its character based on absence of similar examples or style etc.
The thing is about 'how much we know' is, that our core of knowledge in various areas and fields of study is ever increasing. That is why research never ceases. We are never complacent in holdings of data, as these can often be further supported and proven, or equally disproven. In such cases further research might be seen as , to know what something is, sometimes we have to qualify what it isn't, in an oblique perspective.
The purpose of discussions we have, again in my opinion, is to present and exchange ideas and information, bringing together as much data as possible for evaluation. We all have areas of specialty and experience in a broad scope of subject matter. Bringing these together in venues such as ours makes it possible for the advancement of the knowledge in many areas.
It is a difficult and sensitive thing to cast dispersions on an item, and declare it a fake or reproduction, and those kinds of assessments should be carefully worded and explained. I really don't think most would be as cavalier as to dismiss an item as such simply because they had not seen one like it before.
Such an admission would only reveal, depending on the persons expertise, the fact that they had not, but gauged on their experience might be more or less compelling.
Too many collectors insist on neat and concise classifications, and in my view, items may often fall 'outside the box' , so one should carefully qualify such exceptions accordingly.
Those are my thoughts.
