If no one had ever violated the precautionary principle

"But blind pessimism is a blindly optimistic doctrine. It assumes that unforeseen disastrous consequences can not follow from existing knowledge too (or, rather, from existing ignorance). Not all shipwrecks happen to record-breaking ships. Not all unforeseen physical disasters need be caused by physics experiments or new technology . But one thing we do know is that protecting ourselves from any disaster, foreseeable or not , or recovering from it once it has happened, requires knowledge; and knowledge has to be created. The harm that can flow from any innovation that does not destroy the growth of knowledge is always finite; the good can be unlimited. There would be no existing ship designs to stick with , nor records to stay within , if no one had ever violated the precautionary principle."