What is the speed limit where you live? In California, it varies but the maximum is 112.654 kph. In France, the speed limit can run as high as 80.778 mph (actually a couple of yards more).
You don’t see those numbers on road signs, because the California vernacular uses the mile, which is officially defined as 1,609.344 meters, while France uses the kilometer. A meter, of course, is the length of the path travelled by light in vacuum during a time interval of 1/(299,792,458) of a second. It’s obvious when you think about it.
In both jurisdictions, the concept of a speed limit is the same, and the idea is generally justified by public safety, and perhaps fuel conservation, neighborhood nuisances and so on. It’s a common-sense restriction that gives all drivers guidance, and that is meant especially for those lacking in common sense.
The limit is not defined by the maximum speed of a vehicle.
Biology also has its widely accepted rules, which are sometimes given the force of law and sometimes mostly a matter of custom and ethics. Many of these were agreed at a time when there was no immediate prospect of successfully breaking them: a firm line, legally codified in dozens of countries, against human germline intervention, for instance, or the internationally accepted norm of a 14-day limit on human embryo experiments. They give researchers a clear guideline within to work, and they give the public confidence that rogue scientists will not go overboard.
Until very recently, no one had come close to growing a human embryo in a dish for 14 days.
The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.