Daniel Rubin wrote:
At 07:15 AM 6/11/2007, Matt Williams wrote:
I changed the subject line to make it more specific.
I think that Evidence is a tricky, slippery subject. It seems to be
both traces (i.e. records of something) and in many cases, inferences.
Those inferences probably shouldn't be called evidence, but they are
the reason that some data are considered evidence, and others not, and
hence often get included.
Actually, sometimes the interpretation *is* part of the evidence--best
example is medical imaging wherein the radiologist interpretation of the
images are part of the primary evidence (the image is the "raw"
evidence, but you have no result without the radiology interpretation of
the image).
I'd think of the image as of a piece of evidence (of whatever the
patient may suffer from), and the radiologist's interpretation (a
written or spoken statement thereof) as another piece of evidence (of
that the radiologist must have judged the image as a piece of evidence
for whatever the patient may suffer from). And the interpretation is
only indirectly evidence for whatever the patient may suffer from, and
only if we trust or otherwise know the qualifications of the
radiologist. If we doubt, the interpretation is no evidence; and if we
know the interpretation is wrong, it is evidence that the radiologist
made a mistake (and perhaps is not a good one), but certainly not
evidence that the patient suffers from this or that.
Interpretation also transforms raw data into recoded variables that is
also used as evidence, for example in interpreting raw EKG tracings to
give the label of "ventricular tachycardia" or recording a sodium of 150
as "high sodium."
This is a similar case, though if we are based on firm rules (e.g., if X
> 10 then X is high), this recoding is hardly an interpretation, it is
just a lossy translation from quantitative to qualitative form.
But both 'evidence' and 'interpretation' are terms used with many
meanings, and perhaps instead of trying to answer the question 'what is
evidence?' it is better to define the term: 'evidence', for our
purposes, means ...
vQ
