The Declaration of Independence
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will be one master and one ruler, that is, God, over us all, for He is the
author of this law, its promulgator, and its enforcing judge.
Constitutionalism, it should be observed, is a product of this natural
law idea that there are certain unalterable truths, and that kings, parliaments, and judges as well as the citizens are and should be governed
by them.
But if there is such a thing as a natural law of justice, what explains the
fact that the meaning of justice is not exactly the same in all societies?
Since the idea of liberty varies, in one degree or another, from one civilization to the next, how can there be only one objective standard of liberty? When the institution of slavery was debated in the United States in
the early nineteenth century, some Americans argued that slavery was
just and others insisted that it was unjust. Which view is correct? Philosophers have pondered these cultural diversities and differences of opinion for many years. Some have contended that such concepts as liberty
and justice are illusory and mean whatever each society chooses to call
them. A school of thought known as positivism, founded in the nineteenth century by a French philosopher named Auguste Comte, contended, for example, that the only truths were scientific truths, as determined by the scientific or empirical method. Since we cannot prove in a
laboratory what liberty or justice means, suggested Comte, they have no
meaning. Applying such assumptions to laws, the legal positivists asserted that the whole idea of natural law was a myth. A law is a law if it
has passed the legislature, they said, because we can prove that it did or
did not pass. But we cannot scientifically prove that the law protects liberty or justice because we don’t have any way of knowing what these
terms mean. Judges, therefore, should treat all laws the same, the only
test of legitimacy being whether the law was formally enacted by the
rules prescribed. ‘‘Who is to say,’’ said the positivist, ‘‘whether a law is
good or bad? Who is to say what is right or wrong? One man’s opinion
is as good as the next man’s.’’
The natural law philosophers rejected this theory of knowledge. It is
true, they conceded, that ideas about liberty and justice may vary. But the
opinion of one, of many, or even the opinion of all, is not the test. A majority may even declare that a particular ruler, or law, or individual act,