SCIENTIFIC UNCERTAINTY AND THE PRECAUTIONARY PRINCIPLE
Niamh O‟Sullivan *
The relationship between law and science can be said to be an uneasy one, beset by conflicts
of both method and objective.1 Despite this, however, the science-law relationship is often of
considerable importance. Nowhere is this more evident than in relation to environmental
law. Through scientific disciplines such as ecology, chemistry, physics, geosciences and so
on, scientific knowledge is developed which is then used to form the basis of environmental
protection laws. Indeed, scientific research is often initiated with the primary aim of
facilitating the making of law and policies.2 Of course science also plays another role: that of
innovation and the creation of new techniques, methods and technologies, which can impact
the environment, often in a negative way. Thus a symbiotic relationship is established
whereby science not only is needed to inform the law but also is necessarily regulated by it.
The overwhelming reliance on science in developing environmental law has given
rise to difficult issues however. One such issue is how the law can or should regulate risk in
the face of scientific uncertainty. In modernist thought, science was regarded as a higher
universal domain of thought containing ultimate truths and capable of giving definitive,
certain answers. Today, given the massive increase in technologies, methods and forms of
knowledge it has long since been recognised that this is not always the case.3 Despite the
leaps and strides that scientific knowledge has taken in recent years, there is still much we are
uncertain about, and even more but which we are entirely ignorant.4
In environmental law one devise that has developed to deal with situations where it is
clear that we do not know enough, or are not certain enough, is the precautionary principle.
This principle can be seen as part of a rejection of the modernist science-law paradigm, in
*BCL(Hons) Student, University College Cork.
1 MA Berger & LM Solan „The Uneasy Relationship Bet ween Science and the Law: An Essay and
Introduction‟ (2008) 73(3) Brooklyn Law Review 847 orks.bepress.com/lawrence_solan/70> (2 March
2010). Such conflicts can commonly be seen, for example, where t he level of certainty scientists can offer falls
far below the level needed for proving causation in legal arenas. For a more detailed discussion of the
relationship between scientific evide nce and environmental law see Biondi and ot hers (eds) Scientific Evidence
in European Environmental Rule-Making: The Case of the Landfill and End-of-Life Vehicles Directives
(Kluwer Law International New York 2003).
2 One example relates to the obligation on producers or manufacturers of certain products, who have to p rove
their substance is not hazardous b efore it can be authorised by the relevant competent authority. Thus the
impetus for researching the characteristics and properties of that substance is the regulatory requirements rather
than pure scientific interest.
3 For a critique of science in modernity a nd the postmodern incredulity towards metanarratives, see JF Lyotard
The Postmodern Condition: A Report on Knowledge (Manchester University Press Minneapolis 1984).
4 CFCs and asbestos are good examples of ignorance and uncertainty in the past. Scie ntific uncertainty played a
large part in the late reaction to claims of the dangers of asbestos (made as early as 1898) which we now know
only too well are well-founded; asbestos is the main cause of mesothelioma, a very rare cancer of the chest or
abdomen lining, and is also a cause of lung cancer. In relation to ignorance, the effect of chlorofluorocarbons
and their d amage to the ozone layer were not even contemplated prior to 1974, having been considered safe to
use before then. The confirmation of the hole over the Antarctic in 1985 was essentially by accident. See
discussion of these issues and other „acting too late‟ scenarios in European Environmental Agency‟s Repo rt Late
lessons from ea rly warnings: the precaution ary principle 1896 – 2000 (2002) Environmental Issue Report No.
22 (4 May 2009).