We May Brave Human Laws but Cannot Resist Natural Laws

In 1958 the Chinese government of Mao Zedong launched a campaign to eliminate four pests, among them sparrows, which were accused of eating grain. Millions of citizens banged pots and pans to keep the birds in the air until they dropped dead of exhaustion, and the sparrow population was devastated. Without the birds, the insects that they had eaten multiplied, and swarms of locusts attacked the crops. Combined with other policy errors of the Great Leap Forward, the result was one of the worst famines in human history, which killed tens of millions of people. The government could command an enormous campaign, but it could not repeal the web of ecology. The episode is an illustration of the topic, that we may brave human laws but cannot resist natural laws.

The difference between the two kinds of law is basic. A human law is a rule made by people that says what ought to be done. It can be broken, and the lawbreaker may escape detection or punishment. Laws can be repealed, amended and ignored. Natural laws, such as gravity, the conservation of energy and the dependence of life on a healthy environment, describe what happens, and they cannot be repealed or evaded. A person who jumps off a cliff does not need a judge to be punished. Nature enforces its laws automatically and without exception.

This is why people can brave the first kind and not the second. Gandhi broke the salt law in 1930 and was jailed, but the empire could not stop a movement whose moral force was greater than its statutes. Citizens everywhere have defied laws they considered unjust, from the suffragettes to the civil rights marchers. Courts have been evaded and officials bribed. There is a long tradition, from Sophocles' Antigone, of resisting the edicts of kings in the name of a higher law. Defying a human law may be courageous. Defying a natural law is simply foolish.

The same holds for ordinary conduct. A person may exceed the speed limit on a highway and not be caught, but he cannot suspend the laws of motion when the car meets a tree. A contractor may bribe an inspector to pass a bridge, but he cannot bribe the load it will carry, and a bridge that rests on a forged certificate will fall as readily as any other. Natural law is indifferent to the status of the one who defies it.

The history of environmental disaster supports the point. In the 1960s the Soviet Union diverted the Amu Darya and Syr Darya rivers to irrigate cotton in Central Asia. The Aral Sea, once the fourth largest lake in the world, lost most of its water within decades. Fishing villages were left kilometres from the shore, with rusting ships on the dry bed, and the exposed salt and pesticide laden dust damaged the health of local people. The planners had a five year plan, but the lake had a water balance. In Dust Bowl America of the 1930s, farmers ploughed the prairie grasses that held the soil and lost millions of tonnes of topsoil in storms.

The planners had a five year plan, but the lake had a water balance.

Climate change is the largest example. The physics of greenhouse gases was understood in the nineteenth century by Joseph Fourier, John Tyndall and Svante Arrhenius, who calculated in 1896 that doubling carbon dioxide would warm the earth. Governments may agree or not agree to limit emissions, and they may sign accords and break them, but the atmosphere responds only to the amount of gas it receives. The Paris Agreement of 2015 is a human law and its targets can be missed. The rise of the sea is not negotiable. Nature will not consider the political difficulty of cutting emissions or the cost to industry.

Medicine shows a smaller version. Overuse of antibiotics breeds resistance by the plain mechanism of natural selection. Hospitals may pass rules to restrict prescribing, and doctors and patients may ignore them, but bacteria evolve according to the laws of biology. The Chernobyl disaster in 1986 occurred when operators defied safety rules in a test, and the reactor then behaved as its physics demanded. Human error and defiance of human regulations gave nature the occasion, and nature supplied the consequences.

The word law carries an older meaning that also bears on the topic. Cicero wrote in the first century BCE that true law is right reason in agreement with nature, universal and unchanging, and that it cannot be abolished by any senate or people. The natural law tradition holds that moral principles, such as the prohibition on murder and the claim of the innocent to protection, are built into the structure of human nature and society. A regime that tramples on them may enjoy temporary success, but it breeds resentment and ruin. Tyrannies have collapsed because they defied what people could bear.

There are limits to the contrast. Human laws can themselves affect how nature behaves, by shaping the choices that people make. A law that protects forests changes how many trees stand. And the boundary between natural and human systems is porous, since economies and societies have their own regularities, which are discovered and not legislated. Price controls that ignore supply and demand produce shortages, and a government that prints money without limit meets inflation. These are not natural laws in a strict sense, but they behave like them in that they cannot be wished away.

The conclusion is not that rules are useless but that the best rules take account of the laws they cannot change. Human legislation works when it respects the grain of the natural world, as in building codes that allow for earthquakes and in water laws that reflect the rate at which aquifers recharge. Wisdom is the ability to tell which of the constraints we face are choices and which are facts. Many of the disasters of the modern age came from mistaking the second for the first, and the uncomfortable thought is that we may not learn which is which until nature, without anger or delay, has shown us.