Hmmmm, what do you mean by ´solid physical evidence´ ? As one trained and educated in the law, I know what the term means, but what do you mean ? Can archaeology produce ¨solid physical evidence ¨ ? How about document authentication studies ? How about historical records ? As to eyewitness testimony, there are a variety of established tests to test itś veracity. You need to be clearer in what constitutes physical evidence in your mind
It is extremely well-known what constitutes "solid physical evidence" in science. If you have legal training I'm a bit surprised you are not familiar with this, but at least I can be confident you will undertand.
Science relies on
reproducible observations of
nature. Reproducible means something that can be corroborated by more than one observer and preferably in more than one location and/or using more than one technique. The object of this obvious: it is to reduce, as far as possible, bias and error in the reported observation.
So clearly archaeology offers reproducible evidence. The decorated pot, or axe shaft, say, can be examined by more than one person, samples can be carbon-dated by more than one lab, and so on.
(Same sort of thing with fossils, in palaeontology, of course.)
Document authentication is generally done by historians examining the text, rather than scientists, so that is not science. But again, physical samples can be analysed to show age, type of ink and paper, etc, by multiple people in multiple locations. So science can help the historian in that sort of way.
So, as you can perhaps appreciate, eyewitness testimony, of a single supposed event that cannot be reproduced, will not meet the criteria.