What exactly is The Precautionary Principle, and under what circumstances is it applied?
“If you do not know the consequences/risks/outcome(s) of an action, then do not go ahead with the action”
Another, more detailed definition, is expressed by the Wingspread statement :
“When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically. In this context the proponent of an activity, rather than the public, should bear the burden of proof.”
An example : Smoking and Lung Cancer
What would happen if we had to wait until there was a causal link established between smoking and lung cancer? Scientific research for many years had demonstrated that the link was very high. Eventually, the evidence was proved conclusively. In the intervening years, many smokers had died of lung cancer. However, many other people had already quit smoking because they took steps to quit smoking in the light of the growing evidence that smoking was linked to lung cancer. These people had decided to exercise a degree of precaution although there still existed some scientific uncertainty.
When scientific evidence provides ample reason to believe that an activity, technology, or substance may be harmful, it would appear sensible to act to prevent harm. However, If we always wait until scientific certainty has been established, many people may suffer and die .
Still confused?
Further Reading/Information:
http://www.i-sis.org.uk/sapp.php
http://www.mindfully.org/Precaution/Precautionary-Principle-Common-Sense.htm