"In contemporary natural sciences, facts are
increasingly subordinated to the possibility of
measurement, in the broad sense of that term. The
natural sciences display a resistance to any
observation which cannot be fitted into a system of
measurement." [Perelman, 1969 #27] (p. 102)
In EBM, "evidence" is treated as a prescriptive
term.
"Here lies the whole problem of formalism: either
formalism provides a system which is isolated not
merely from its applications, but even from the
living thought which must understand and manipulate
it, that is, integrate it into preexistent mental
structures; or it will have to be interpreted and
will effect identification which can be ascribed to
quasi-logical argumentation. Even if these
identifications are not contested during a given
period of scientific evolution, it would be
dangerous for ulterior progress of thought to
regard them as necessary and grant them the selfevidence on attributes to assertions which are no
longer open to discussion." (p. 212)[Perelman, 1969
#27]
For each type of healthcare issue (diagnosis,
prognosis, therapy, assessing harm), Sackett et al
are coming up with statements of conditions that
must be met in order for evidence to be valid…their
choice of definition of "valid evidence."
Is there a tension between the way that Sackett is
defining "valid evidence" and the way that readers
will define these same words as they are understood
in the tradition of the language? Will readers be
resistant to Sackett's definition of "valid
evidence"?
"…the use of definition in argumentation implies
the possibility of several definitions, borrowed
from common usage or created by the writer, among
which a choice must be made….related terms
themselves are constantly interacting, not only
with a set of other terms in the same language or
in other languages which can be related to the
original, but also with the totality of other
possible definitions of the same term. These
interactions cannot be eliminated; generally, they
are even essential to the significance of the
reasoning. However, once the choices I made,
whether it be presented as self-evident or whether
it be supported by arguments, the definition which
is used is regarded as an expression of an
identity, indeed as the only satisfactory one under
the circumstances, and the equivalent terms,
detached in a sense from their ties and their
background, can be considered as logical
substitutes for each other." (p. 214) [Perelman,
1969 #27]