Maybe we will take such a principle seriously when it is consistently applied – such as to when the government regulates market activity, or in how much power to entrust to the politicos in the first place. But of course as Obama Administration official Cass Sunstein smartly recognizes:
The precautionary principle has been highly influential in legal systems all over the world. In its strongest and most distinctive forms, the principle imposes a burden of proof on those who create potential risks, and it requires regulation of activities even if it cannot be shown that those activities are likely to produce significant harms. Taken in this strong form, the precautionary principle should be rejected, not because it leads in bad directions, but because it leads in no directions at all. The principle is literally paralyzing – forbidding inaction, stringent regulation, and everything in between. The reason is that in the relevant cases, every step, including inaction, creates a risk to health, the environment, or both. This point raises a further puzzle. Why is the precautionary principle widely seen to offer real guidance? The answer lies in identifiable cognitive mechanisms emphasized by behavioral economists.
And speaking of the topic: here’s our government throwing (pre)caution into the wind.