Part I. Introduction. Natural Law. Chapter I. Natural Law and Reason.
Among intellectuals who consider themselves scientific, the phrase the nature of man is
apt to have the effect of a red flag on a bull. Man has no nature, is the modern rallying
and Typical of the Sentiment of Political Philosophers Today was the assertion of a distinguished political theorist some years ago, before a meeting of the American Political Science Association, that man's nature is a purely theological concept that must be dismissed from any scientific discussion.
In the controversy over man's nature and over the broader and more controversial concept of natural law, both sides have repeatedly proclaimed that natural law and theology are inextricably intertwined.
As a result, many champions of natural law, in scientific or philosophic circles, have gravely weakened their case by implying that rational philosophical methods alone cannot establish such a law,
that theological faith is necessary to maintain the concept.
On the other hand, the opponents of natural law have gleefully agreed, since faith in
the supernatural is deemed necessary to believe in natural law, the latter concept must be
tossed out of scientific secular discourse and be consigned to the arcane sphere of the
divine studies.
In consequence, the idea of a natural law founded on reason and rational inquiry has
been virtually lost.
The believer in a rationally established natural law must then face the hostility of both camps,
the one group sensing in this position an antagonism toward religion, and the other
group suspecting that God and mysticism are being slipped in by the back door.
To the first group, it must be said that they are reflecting an extreme Augustinian position,
which held that faith, rather than reason, was the only legitimate tool for investigating
man's nature and man's proper ends.
In short, in this Fideist tradition, theology had completely displaced philosophy.
The Thomist tradition, on the contrary, was precisely the opposite, vindicating the independence
If belief in a systematic order of natural laws open to discovery by man's reason is
per se anti-religious, then anti-religious also were St. Thomas and the later scholastics,
as well as the devout Protestant jurist Hugo Grotius.
The statement that there is an order of natural law, in short, leaves open the problem of
whether or not God has created that order, and the assertion of the viability of man's
reason to discover the natural order leaves open the question of whether or not that reason
was given to man by God.
The assertion of an order of natural laws discoverable by reason is by itself neither
pro nor anti-religious.
As this position is startling to most people today, let us investigate this Thomistic position
a little further.
The statement of absolute independence of natural law from the question of the existence
of God was implicit rather than flatly asserted in St. Thomas himself.
But like so many implications of Thomism, it was brought forth by Suarez and the other
brilliant Spanish scholastics of the late 16th century.
The Jesuit Suarez pointed out that many scholastics had taken the position that the natural law
of ethics, the law of what is good and bad for man, does not depend upon God's will.
Indeed, some of the scholastics had gone so far as to say that, even though God did not
exist or did not make use of his reason or did not judge rightly of things, if there
There is in man such a dictate of right reason to guide him, it would have had the same nature
of law as it now has.
Or, as a modern Thomist philosopher declares, if the word natural means anything at all,
it refers to the nature of a man, and when used with law, natural must refer to an ordering
that is manifested in the inclinations of a man's nature, and to nothing else.
Hence, taken in itself, there is nothing religious or theological in the natural law of Aquinas.
Dutch Protestant jurist Hugo Grotius declared, in his Dei Uri Belli Ac Pacis, 1625,
What we have been saying would have a degree of validity even if we should concede that
which cannot be conceded without the utmost wickedness, that there is no God.
And again, measureless as is the power of God, nevertheless it can be said that there
are certain things over which that power does not extend.
Just as even God cannot cause that two times two should not make four, so he cannot cause
that which is intrinsically evil be not evil.
John Trev concludes that,
Grotius' definition of natural law has nothing revolutionary.
When he maintains that natural law is that body of rules which man is able to discover by the use of his reason,
he does nothing but restate the scholastic notion of a rational foundation of ethics.
Indeed, his aim is rather to restore that notion,
which had been shaken by the extreme Augustinianism of certain Protestant currents of thought.
When he declares that these rules are valid in themselves, independently of the fact that
God willed them, he repeats an assertion which had already been made by some of the schoolmen.
Grotious aim, Dontrev adds, was to construct a system of laws which would carry conviction
in an Age in Which Theological Controversy Was Gradually Losing the Power to Do So.
Grotius and his juristic successors, Pufendorf, Borlamacqui and Fattel, proceeded to elaborate
this independent body of natural laws in a purely secular context, in accordance with
their own particular interests, which were not, in contrast to the school men, primarily
theological.
Indeed, even the 18th century rationalists, in many ways dedicated enemies of the scholastics,
were profoundly influenced in their very rationalism by the scholastic tradition.
Thus let there be no mistake, in the Thomistic tradition natural law is ethical as well as
physical law, and the instrument by which man apprehends such law is his reason, not
without faith, or intuition, or grace, revelation, or anything else.
In the contemporary atmosphere of sharp dichotomy between natural law and reason, and especially
amid the irrationalist sentiments of conservative thought, this cannot be underscored too often.
Hence St. Thomas Aquinas, in the words of the eminent historian of philosopher, Father
Professor Copleston emphasized the place and function of reason in moral conduct.
He, Aquinas, shared with Aristotle the view that it is the possession of reason which
distinguished man from the animals, and which enables him to act deliberately in view of
the consciously apprehended end, and raises him above the level of purely instinctive
behavior.
Aquinas, then, realized that men always act purposively, but also went beyond this to
argue that ends can also be apprehended by reason, as either objectively good or bad
for man.
For Aquinas, then, in the words of Copleston, there is therefore room for the concept of
right reason, reason directing man's acts to the attainment of the objective good for
man.
Moral conduct is therefore conduct in accord with right reason.
If it is said that moral conduct is rational conduct, what is meant is that it is conduct
in accordance with right reason, reason apprehending the objective good for man and dictating the
means to its attainment.
In natural law philosophy, then, reason is not bound, as it is in modern posthumian philosophy,
to be a mere slave to the passions, confined to cranking out the discovery of the means
to arbitrarily chosen ends, for the ends themselves are selected by the use of reason, and right
reason dictates to man his proper ends as well as the means for their attainment.
For the Thomist or natural law theorist, the general law of morality for man is a special
is a special case of the system of natural law governing all entities of the world, each
with its own nature and its own ends.
For him, the moral law is a special case of the general principles that all finite things
move toward their ends by the development of their potentialities.
And here we come to a vital difference between inanimate or even non-human living creatures
and man himself.
For the former are compelled to proceed in accordance with the ends dictated by their
natures, whereas man, the rational animal, possesses reason to discover such ends, and
the free will to choose.
Which doctrine, natural law or those of its critics, is to be considered truly rational,
was answered incisively by the late Leo Strauss in the course of a penetrating critique of
Value Relativism in Political Theory of Professor Arnold Brecht.
For in contrast to natural law, positivistic social science is characterized by the abandonment
of reason or the flight from reason.
According to the positivistic interpretation of relativism, which prevails in present-day
social science, reason can tell us which means are conducive to which ends.
Reason cannot tell us which attainable ends are to be preferred to other attainable ends.
Reason cannot tell us that we ought to choose attainable ends.
If someone loves him who desires the impossible, reason may tell him that he acts irrationally,
but it cannot tell him that he ought to act rationally, or that acting irrationally is
acting badly or basely.
If rational conduct consists in choosing the right means for the right end, relativism
teaches in effect that rational conduct is impossible.
Finally, the unique place of reason in natural law philosophy has been affirmed by the modern
Thomistic philosopher, the late Father John Toohey.
Toohey defined sound philosophy as follows.
Philosophy in the sense in which the word is used when scholasticism is contrasted with
and Other Philosophies is an attempt on the part of man's unaided reason to give a fundamental
explanation of the nature of things.