This question, specific as it is, forms part of the lively theoretical debate on the
relationship between scientific evidence and criminal trials, in search of a
problematic balance between a theory – not insensitive to certain suggestions of
interpretive stances from beyond our borders – that tends to put an increasing
amount of weight on the contributions of science, even if not validated by the
scientific community; and a theory that insists on the primacy of law and postulates
that, in deference to the rules of criminal procedure itself, only those scientific
experiments validated according to commonly accepted methodological canons may
be allowed to enter.
This cultural debate, while respecting the principle of freely-held opinion of the
judge, also proposes to critically reexamine the now-obsolete and dubiously credible
notion of the judge as “peritus peritorum” [expert of experts]. Indeed, this old
maxim expresses a cultural model that is no longer current, and is in fact decidedly
anachronistic, at least to the extent that it expects to assign to the judge a real
ability to master the flow of scientific knowledge that the parties pour into the
proceeding; a more realistic formulation, by contrast, sees the judge as wholly
oblivious to those contributions, which are the fruit of a scientific training that he or
she does not, need not, and cannot possess. This is all the more true with regard to
genetic science, whose complex methods require a specific training in forensic
genetics, chemistry, and molecular biology, drawing upon a knowledge base that is
light-years away from the purely humanistic and juridical education of a magistrate.
The consequence of acknowledging, as is inevitable, this state of legitimate
ignorance on the part of the judge, and therefore their inability to “autonomously”
master scientific evidence, cannot, however, be an uncritical placing of trust, which
would be tantamount – perhaps on account of a misunderstood notion of freely-held
opinion and of an equally misunderstood concept of “expert of experts” – to the
substantial abdication of their own role by means of a fideistic acceptance of
contributions by experts to whom the resolution of the case – and thus the
responsibility of deciding it – would be delegated.