Abstract

The basic idea underlying a precautionary principle is often summarized as “better safe than sorry.” Even if it is uncertain whether an activity will lead to harm, for example, to the environment or to human health, measures should be taken to prevent harm. This demand is partly motivated by the consequences of regulatory practices of the past. Often, chances of harm were disregarded because there was no scientific proof of a causal connection between an activity or substance and chances of harm, for example, between asbestos and lung diseases. When this connection was finally established, it was often too late to prevent severe damage. However, it is highly controversial how the vague intuition behind “better safe than sorry” should be understood as a principle. As a consequence, we find a multitude of interpretations ranging from decision rules over epistemic principles to procedural frameworks. To acknowledge this diversity, it makes sense to speak of precautionary principles (PPs) in the plural. PPs are not without critices. For example, it has been argued that they are paralyzing, unscientific, or promote a culture of irrational fear. This article systematizes the different interpretations of PPs according to their functions, gives an overview about the main lines of argument in favor of PPs, and outlines the most frequent and important objections made to them.