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Canadian DNA Jurisprudence and Changing Forensic Practice 113
Should traditional fields of forensics accept the sort of changes that are being
proposed by the NAS, it would make for a paradigmatic change 6 in the way the
forensic sciences function. It will also fundamentally change the context in which
forensic evidence is presented in courtrooms. Lawyers, courts, police officers,
prosecutors, and all the legal actors who have become accustomed to forensic
evidence presented in a particular way will have to adjust to a new way of thinking
about forensic evidence. The model for the way this evidence may end up being
presented should follow the model adopted by DNA evidence, and thus we might
expect that DNA evidence and the way it is evaluated, presented, and validated
will become the dominant paradigm for forensic evidence generally. This would
represent a fundamental, normative change in the way forensic science is
practiced by forensic science and in the way that it is presented to the courts. 7
It seems likely that any changes to forensic practice resulting from the NAS
report will likely spread to Canadian forensics as it has implications for all
forensic practitioners, whether they are in the United States or elsewhere.
Anecdotally, in my conversations with Canadian forensics practitioners they
already talk about its impact.
For the law generally, the switch to a DNA-style model of forensic practice
may not at first seem to be problematic. It appears to be a welcome improvement
for a type of evidence that has seemed increasingly inadequate in recent years. 8
The law has had to adapt to the coming of DNA evidence, so one might think
that it would be well prepared for the “DNAification” of forensic evidence more
generally.
Looking at Canadian law, it is not clear that this latter assumption is true. As
this paper will show, Canadian courts had some specific difficulties with DNA
evidence, and it is probable that some of these difficulties may resurface when
they are confronted with traditional forensics translated to fit the DNA paradigm.
In particular, questions related to how judges, juries, and the law more generally
confront probabilistic evidence will become germane. These are questions that,
this paper will show, were only partially addressed during the initial phases of
DNA acceptance in Canada, and it is reasonable to expect that similar questions
may be raised when and if traditional forensics disciplines begin to follow the
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Paradigmatic change refers to the process whereby a normative model of scientific practice (or
paradigm) changes. See Thomas Kuhn, The Structure of Scientific Revolutions, 3rd (Chicago:
University of Chicago Press, 1996).
See Paul C Giannelli, “Forensic Science: Under the Microscope” (2008) 34 Ohio NU L Rev 315
and Michael J Saks & Jonathan J Koehler, “Review, The Coming Paradigm Shift in Forensic
Identification Science,” (2005) 309: 5736 Science 892 for a discussion of the potential for a
paradigm shift in the way forensic evidence is handled in the United States.
There is a developing literature aimed at the American defence bar that focuses on
demonstrating limitations with conventional forensic evidence techniques. See Adina Schwartz,
“Challenging Firearms and Toolmark Identification” (2008) 32 Champion 10 for an example of
the approaches being taken.