Society & Environment

Technological Nightmares (Lecture): Note on the “Precautionary Principle”




Series: Pardee Center Distinguished Lecture Series
Date: October 2003
Location: Frederick S. Pardee Center for the Study of the Longer-Range Future, Boston University, Boston, MA

Note on the “Precautionary Principle”

There are two points of view when we face risk and uncertainties in our research. One is based on the precautionary principle. The precautionary principle says that when there is any risk of a major disaster, no action should be permitted that increases the risk. If, as so often happens, an action promises to bring substantial benefits together with some risk of a major disaster, no balancing of benefits against risks is to be allowed. Any action carrying a risk of a major disaster must be prohibited, regardless of the costs of prohibition.

The opposing point of view holds that risks are unavoidable, that no possible course of action or inaction will eliminate risks, and that a prudent course of action must be based on a balancing of risks against benefits and costs. In particular, when any prohibition of dangerous science and technology is contemplated, one of the costs that must be considered is the cost to human freedom. Freeman Dyson calls the first point of view precautionary, the second libertarian.

Wilfred Beckerman summarizes the precautionary principle in the following way: “It is asserted that faced with a possibility, however remote, of some catastrophic development, prudent policy demands that whatever action is required to prevent it be taken.” This implies that the required action has to be taken, however high the costs. He uses the following illustration. When we buy a padlock to prevent our bicycle from being stolen, we compare the value of the bicycle with the chances of theft and the cost of the padlock. If the bicycle is worthless and the cost of the padlock is very high, we don’t buy it.

To apply the precautionary principle means that irrespective of the chances of future loss, the scale of the loss, and the costs of preventing it, one must incur these costs. We have the choice between (1) accepting some remote and unquantifiable possibility of severe effects and (2) certain catastrophe if draconian policies are adopted to avoid it. The economic costs of avoiding all conceivable possibilities of a catastrophe could be astronomic. Pascal’s wager is an extreme version of the precautionary principle.



This is a chapter from Technological Nightmares (Lecture).
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Longer-Range, F. (2014). Technological Nightmares (Lecture): Note on the “Precautionary Principle”. Retrieved from


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