Precautionary principle

The precautionary principle (or precautionary approach) is a broad epistemological, philosophical and legal approach to innovations with potential for causing harm when extensive scientific knowledge on the matter is lacking. It emphasizes caution, pausing and review before leaping into new innovations that may prove disastrous.^[1] Critics argue that it is vague, self-cancelling, unscientific and an obstacle to progress.^[2][3]

In an engineering context, the precautionary principle manifests itself as the factor of safety, discussed in detail in the monograph of Elishakoff.^[4] It was apparently suggested, in civil engineering, by Belidor^[5] in 1729. Interrelation between safety factor and reliability^[6][5][7] is extensively studied by engineers and philosophers.

The principle is often used by policy makers in situations where there is the possibility of harm from making a certain decision (e.g. taking a particular course of action) and conclusive evidence is not yet available. For example, a government may decide to limit or restrict the widespread release of a medicine or new technology until it has been thoroughly tested. The principle acknowledges that while the progress of science and technology has often brought great benefit to humanity, it has also contributed to the creation of new threats and risks. It implies that there is a social responsibility to protect the public from exposure to such harm, when scientific investigation has found a plausible risk. These protections should be relaxed only if further scientific findings emerge that provide sound evidence that no harm will result.

The principle has become an underlying rationale for a large and increasing number of international treaties and declarations in the fields of sustainable development, environmental protection, health, trade, and food safety,^[8] although at times it has attracted debate over how to accurately define it and apply it to complex scenarios with multiple risks. In some legal systems, as in law of the European Union, the application of the precautionary principle has been made a statutory requirement in some areas of law.^[9]