There is a good discussion of the relative subjectivity of information used to make diagnoses in the current A Piece of My Mind at JAMA. Unfortunately, it requires a subscription, but you should be able to get a copy at the local library or from someone with access to a JAMA subscription.
Sherlock Holmes would seem to be the epitome of the person who objectively assesses facts. There are four footnotes and two of them are from Sherlock Holmes stories (and one is from a Bob Seger song). This is not an article that claims that only the objective matters, but that it is important to realize just how subjective a lot of our objective information can be.
No. It is not some post-modernist, everybody is entitled to their own reality silliness.
Sherlock Holmes can be a good choice for pointing out some of the ways we confuse subjective (influenced by each person’s perspective) and objective (free from any interpretation).
Arthur Conan Doyle, speaking as Sherlock Holmes, observed that “It is of the highest importance in the art of detection to be able to recognize, out of a number of facts, which are incidental and which vital. Otherwise your energy and attention must be dissipated instead of being concentrated.”1 
It is ironic that Doyle and the magician Houdini ended their friendship over Doyle’s refusal to accept that Houdini did not have real magical powers. The author of books about one of fiction’s characters least superstitious and least likely to be fooled was actually very superstitious and very easily fooled.
Surprisingly, there is no reference to Rashomon, which may be the clearest explanation of the way events may be seen differently by different observers of the same events. The events are the same, but the perspective completely changes the narrative. The bandit’s story, the wife’s story, the samurai’s story, and the woodcutter’s story all present the same story as different stories.
The article is very well written and encourages us to be much less certain of what is critical information and what is objective information. We need to constantly be looking for evidence that disconfirms our hypotheses.