Physical evidence:
is extremely strong because the evidence is nearly impossible to refute and is objective, meaning that it is subject to minimal human interpretation.
Testimonial evidence:
on the other hand, testimonial evidence although oftentimes is strong and nearly always believed by juries (judging by the conviction rates), it is recognised by the courts that witnesses can and do lie on the stand.
You've reminded me of psychology and the differences between qualitative and quantitative data. The qualitative is newpaper articles, testimony and interviews etc while quantitative represents data in numerical form.
But even with statistics, there are further divisions between descriptive and inferential. In order to assume correlates or connections, inferential statistics is needed.
When you mention things like physical evidence it reminds me of the need to interpret that evidence in the light of psychological insight. Here we apply inferential psychology to assess the physical evidence. Just because this person wielded the gun, the knife etc does not necessarily tell the whole story.
It is within these lines of evidence - enlightend by psychological insight, that the closest approximation of truth can be attained.
Great share thanks