The network of the precautionary principle under EU law, by Alessandra Donati

The purpose of this post is to provide an overview of the research that I carried out during my PhD at the University Paris 1 Panthéon Sorbonne on the precautionary principle under EU law. The main findings of this study are now published as a book: Donati A., Le principe de precaution en droit de l’Union européenne, Bruylant, 2021. In this work, by acknowledging the flexible and complex nature of the precautionary principle and by referring to methodological pluralism, I provide a polycentric interpretation of this principle based on diversity rather than uniformity. The polycentric interpretation is anchored in the construction of the network of the precautionary principle. This allows for the unitas multiplex between the different definitions and applications of this principle to be identified and assessed. The core claim of my research is that the polycentric interpretation of the precautionary principle can be built on two concepts: anticipation and action which represent the two main knots of its network. These knots are not isolated, but they are connected via some links to other knots that constitute the main concepts allowing identifying and applying the precautionary principle under EU law.

A widespread and controversial principle

Provided for by article 191 para. 2 of the Treaty on the Functioning of the European Union, the precautionary principle is a founding principle of the European environmental policy. Moreover, since the National Farmers’ Union and the United Kingdom/Commission judgments of 5 May 1998 (C-157/96), the Court of Justice of the European Union has also repeatedly applied the precautionary principle in the field of public health (see, for example, C-132/03 and C-504/04). Although it is one of the most evoked principles, its meaning and effects are not univocally conceived, and the precautionary principle remains a controversial principle. Due to its diverging interpretations and applications, the precautionary principle is largely misunderstood, and decision-makers often neglect its implementation in the most sensitive cases concerning the protection of the environment and public health.

A post-modern principle

Against this backdrop, the core claim of my research is that to foster the application of the precautionary principle, it is necessary to make a methodological shift in the way in which this principle is interpreted under EU law. This methodological shift shall be based on the acceptance of the post-modern nature of the precautionary principle. From the late 1970s onwards, we have witnessed the progressive deconstruction of the traditional paradigm of modernity because it was incapable of describing the contemporary era or facing its challenges. This evolution is reflected in the questioning of the primacy of reason, leading to a corresponding loss of confidence in science and disillusionment with the idea of progress. The emphasis is now on disorder, complexity, indeterminacy, and relativism, which are seen as the main characteristics of the “post-modern condition” (F. Lyotard, La condition post-moderne, Paris, Éditions de Minuit, 1979).

Under the theoretical framework of post-modernism, the analysis of the precautionary principle is utterly significant since it can be defined as a paradigmatic principle of post-modern law. Indeed, the precautionary principle shares the same features of flexibility and complexity, which belong to post-modern principles.

First, the flexibility of the precautionary principle is due to its vague and soft nature. On the one hand, the norms on which the precautionary principle is based are limited to mentioning it without defining its content and conditions of implementation. This implies that it is not possible to deduce precisely the obligations arising from the precautionary principle. In the absence of predetermination in the text of the law, the meaning of this principle depends mainly on the interpretation given to it by the decision-makers and the judge who co-determine the scope of this principle. On the other hand, even if today, a large majority of the doctrine recognises that the precautionary principle is a binding legal principle, its binding force is weak, and it is limited to the procedural side.

Second, the precautionary principle is complex because it operates at the intersection of different disciplines. The precautionary principle is a legal principle, but its understanding is not limited to the legal domain. Analysing the precautionary principle involves addressing the relationship between law and science; between law and political science, it also explains how ethics, morality, philosophy, economics, and sociology influence the authorities when making decisions about risk.

Methodological pluralism

In this context, which methodology shall be used to analyse the precautionary principle and support the envisaged shift in the interpretation of this principle? The choice that I make is to refer to methodological pluralism (G. Otis (eds), Méthodologie du pluralisme juridique, Karthala, 2012). This proves to be an adequate methodology to master the flexibility and complexity of the precautionary principle.

Methodological pluralism is part of the theoretical trend of post-modernism and is presented as a new approach to studying legal reality.With post-modernism, the foundations of law become more complex because of changes in contemporary society. Similarly, with methodological pluralism, the method used to analyse the legal system evolves to consider its complexity. In a legal system strongly marked by the presence of antinomies, lawyers are required to look for elements of coherence and consistency. In other words, lawyers shall seek the commonalities within the different norms and the multiple actors of our legal system. The order that we are looking for is not monolithic and static but polycentric and dynamic. Methodological pluralism takes the network metaphor used to describe post-modern law and applies it to the lawyer’s work. The etymology of the term network, from the Latin retis, refers to the idea of a net. The use of the term evokes a textile metaphor. The network is a weft made up of elements described as knots connected by links that ensure their interconnection and interaction.

The network of the precautionary principle

The knots of the precautionary principle correspond to the key concepts that make it possible to identify this principle. The construction of the unitas multiplex presupposes the establishment of stable points in the interpretation of the precautionary principle around which to build a network. To do so, I realised a conceptual work of aggregation and disaggregation of the precautionary principle’s components. First, I identified the macro-concepts that make it possible to understand the scope of the precautionary principle. Thus, for example, I extrapolated the concepts of qualification by law of uncertain risks and evaluation by science of uncertain risks, and Iadded them to the network of this principle. In a second step, I decomposed these macro knots to study them. For each of the macro knots, I tried to define their components. For example, the study of the concept of qualification by the law of uncertain risks allowed me to identify the elements and objectives of this qualification. In the same vein, the study of the elements revealed that these are the risk and uncertainty. Furthermore, in a crescendo of decomposition, inherent to an increasing degree of conceptualisation, I realised that the risk could be disaggregated into two separate concepts: a real risk and a serious risk. The first refers to the mathematical and scientific dimension of risk, the second to its social and political nature. In successive stages, I conducted the same work of breaking down the concept for all the knots of the precautionary principle. The process resulted in a disordered set of key concepts representing the knots of the precautionary principle’ network. However, it is not enough to detect the knots of the network, it is also necessary to trace the links that connect them.

Within the precautionary principle’s network, the coordination between the knots is ensured by the links. Links are information vehicles that indicate the quality and quantity of data available on the interactions between the knots of the precautionary principle based on its different sources. The analysis of the links allows understanding of whether the relationship between two knots is established and the degree of confidence that can be assigned to this interaction considering the available information. Against this backdrop, I first considered that a link is strong when a lot of information is available, and there is a convergence between the sources (legislation, case-law, and legal scholarship) of the precautionary principle as to the relationship established between two knots of this principle. Second, I qualified a link as weak when the sources of the precautionary principle are not numerous and/or do not fully converge in the interpretation or application of certain knots. Third, I appraised a link as absent, when the connection between two knots of the precautionary principle is not established.

To describe the dynamics of the precautionary principle’s network, I referred to a metaphor borrowed from the hub and spoke theory commonly used in computer science and transport. Unlike the ring network model (where knots are connected to each other in a chain), in the precautionary principle’s network, the knots are not all linked to each other, but they are connected to hubs. The polycentric interpretation of the precautionary principle that I am looking for can be built on two concepts that can be understood as the hubs of the precautionary principle: anticipation and action. Anticipation and action represent the two central connection points that govern the circulation between the knots of the precautionary principle. The link between anticipation and action is strong. On the one hand, anticipation is the sine qua non-condition of action. Action based on the precautionary principle presupposes the anticipation by decision-makers of the time for action by taking into account uncertain risks. On the other hand, action is the necessary consequence of anticipation. Although decision-makers have anticipated the time for action by considering uncertain risks, without an action based on the precautionary principle, the occurrence of these risks could not be prevented or managed. Thus, the objective of a high level of environmental and public health protection could not be achieved.

In the precautionary principle’s network, the hubs, anticipation and action, are connected via links to other knots. The precautionary principle’s network can therefore be separated into two different networks originating, respectively, in the anticipation and action hubs. For a detailed identification and explanation of the functioning of the knots and links of the precautionary principle, including their graphical representation, please refer to Donati A., Le principe de précaution en droit de l’Union européenne, Bruylant, 2021.

Posted by Alessandra Donati (Luxembourg)

Alessandra Donati is a postdoctoral researcher at the University of Luxembourg, a lecturer at SciencesPo (Campus of Nancy) and a qualified lawyer in Italy and France. She specialises in European environmental and public health law with a particular focus on the issue of risk regulation. Before joining the University of Luxembourg, Alessandra was Senior Research Fellow at the Max Planck Institute Luxembourg. Previously, she worked in two law firms in Italy (Chiomenti) and France (Castaldi Partners). Alessandra studied at the Bocconi University of Milan (bachelor and master in law), at the Politecnica delle Marche University (bachelor and master in management) and the Paris 1 Panthéon Sorbonne University (LLM in European law). She holds a doctorate in law from the University of Paris 1 Panthéon Sorbonne. Alessandra is editor in chief of the European Journal of Consumer Law (REDC).

Suggested citation: A Donati, “The network of the precautionary principle under EU law”, available at