Question 94: Of the Natural Law
We must now
consider the natural law; concerning which there are six points of inquiry:
1. What is the
natural law?
2. What are the
precepts of the natural law?
3. Whether all acts
of virtue are prescribed by the natural law?
4. Whether the
natural law is the same in all?
5. Whether it is
changeable?
6. Whether it can
be abolished from the heart of man?
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Article 1. Whether the natural law is a
habit?
Objection 1. It would seem that
the natural law is a habit. Because, as the Philosopher says (Ethic. ii, 5),
"there are three things in the soul: power, habit, and passion." But
the natural law is not one of the soul's powers: nor is it one of the passions;
as we may see by going through them one by one. Therefore the natural law is a
habit.
Objection 2. Further, Basil
[*Damascene, De Fide Orth. iv, 22] says that the conscience or "synderesis
is the law of our mind"; which can only apply to the natural law. But the
"synderesis" is a habit, as was shown in I, 79, 12.
Therefore the natural law is a habit.
Objection 3. Further, the
natural law abides in man always, as will be shown further on (A. 6). But man's
reason, which the law regards, does not always think about the natural law.
Therefore the natural law is not an act, but a habit.
On the contrary, Augustine says (De
Bono Conjug. xxi) that "a habit is that whereby something is done when
necessary." But such is not the natural law: since it is in infants and in
the damned who cannot act by it. Therefore the natural law is not a habit.
I answer that, A thing may be
called a habit in two ways. First, properly and essentially: and thus the
natural law is not a habit. For it has been stated above (Q. 90, A.1, ad 2)
that the natural law is something appointed by reason, just as a proposition is
a work of reason. Now that which a man does is not the same as that whereby he
does it: for he makes a becoming speech by the habit of grammar. Since then a habit
is that by which we act, a law cannot be a habit properly and essentially.
Secondly, the term
habit may be applied to that which we hold by a habit: thus faith may mean that
which we hold by faith. And accordingly, since the precepts of the natural law are
sometimes considered by reason actually, while sometimes they are in the reason
only habitually, in this way the natural law may be called a habit. Thus, in
speculative matters, the indemonstrable principles are not the habit itself
whereby we hold those principles, but are the principles the habit of which we
possess.
Reply to Objection
1. The Philosopher proposes there to discover the genus of
virtue; and since it is evident that virtue is a principle of action, he
mentions only those things which are principles of human acts, viz. powers,
habits and passions. But there are other things in the soul besides these
three: there are acts; thus "to will" is in the one that wills;
again, things known are in the knower; moreover its own natural properties are
in the soul, such as immortality and the like.
Reply to Objection
2. "Synderesis" is said to be the law of our mind,
because it is a habit containing the precepts of the natural law, which are the
first principles of human actions.
Reply to Objection
3. This argument proves that the natural law is held
habitually; and this is granted.
To the argument
advanced in the contrary sense we reply that sometimes a man is unable to make
use of that which is in him habitually, on account of some impediment: thus, on
account of sleep, a man is unable to use the habit of science. In like manner,
through the deficiency of his age, a child cannot use the habit of
understanding of principles, or the natural law, which is in him habitually.
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Article 2. Whether the natural law
contains several precepts, or only one?
Objection 1. It would seem that
the natural law contains, not several precepts, but one only. For law is a kind
of precept, as stated above (Q. 92, A. 2). If therefore there were many
precepts of the natural law, it would follow that there are also many natural
laws.
Objection 2. Further, the
natural law is consequent to human nature. But human nature, as a whole, is
one; though, as to its parts, it is manifold. Therefore, either there is but
one precept of the law of nature, on account of the unity of nature as a whole;
or there are many, by reason of the number of parts of human nature. The result
would be that even things relating to the inclination of the concupiscible
faculty belong to the natural law.
Objection 3. Further, law is
something pertaining to reason, as stated above (Q. 90, A. 1). Now reason is
but one in man. Therefore there is only one precept of the natural law.
On the contrary, The precepts of
the natural law in man stand in relation to practical matters, as the first
principles to matters of demonstration. But there are several first
indemonstrable principles. Therefore there are also several precepts of the
natural law.
I answer that, As stated above
(Q. 91, A. 3), the precepts of the natural law are to the practical reason,
what the first principles of demonstrations are to the speculative reason;
because both are self-evident principles. Now a thing is said to be
self-evident in two ways: first, in itself; secondly, in relation to us. Any
proposition is said to be self-evident in itself, if its predicate is contained
in the notion of the subject: although, to one who knows not the definition of
the subject, it happens that such a proposition is not self-evident. For
instance, this proposition, "Man is a rational being," is, in its
very nature, self-evident, since who says "man," says "a
rational being": and yet to one who knows not what a man is, this
proposition is not self-evident. Hence it is that, as Boethius says (De
Hebdom.), certain axioms or propositions are universally self-evident to all;
and such are those propositions whose terms are known to all, as, "Every
whole is greater than its part," and, "Things equal to one and the
same are equal to one another." But some propositions are self-evident
only to the wise, who understand the meaning of the terms of such propositions:
thus to one who understands that an angel is not a body, it is self-evident
that an angel is not circumscriptively in a place: but this is not evident to
the unlearned, for they cannot grasp it.
Now a certain order
is to be found in those things that are apprehended universally. For that
which, before aught else, falls under apprehension, is "being," the
notion of which is included in all things whatsoever a man apprehends.
Wherefore the first indemonstrable principle is that "the same thing
cannot be affirmed and denied at the same time," which is based on the
notion of "being" and "not-being": and on this principle
all others are based, as is stated in Metaph. iv, text. 9. Now as
"being" is the first thing that falls under the apprehension simply,
so "good" is the first thing that falls under the apprehension of the
practical reason, which is directed to action: since every agent acts for an
end under the aspect of good. Consequently the first principle of practical
reason is one founded on the notion of good, viz. that "good is that which
all things seek after." Hence this is the first precept of law, that
"good is to be done and pursued, and evil is to be avoided." All
other precepts of the natural law are based upon this: so that whatever the
practical reason naturally apprehends as man's good (or evil) belongs to the
precepts of the natural law as something to be done or avoided.
Since, however,
good has the nature of an end, and evil, the nature of a contrary, hence it is
that all those things to which man has a natural inclination, are naturally
apprehended by reason as being good, and consequently as objects of pursuit,
and their contraries as evil, and objects of avoidance. Wherefore according to
the order of natural inclinations, is the order of the precepts of the natural
law. Because in man there is first of all an inclination to good in accordance
with the nature which he has in common with all substances: inasmuch as every
substance seeks the preservation of its own being, according to its nature: and
by reason of this inclination, whatever is a means of preserving human life,
and of warding off its obstacles, belongs to the natural law. Secondly, there is
in man an inclination to things that pertain to him more specially, according
to that nature which he has in common with other animals: and in virtue of this
inclination, those things are said to belong to the natural law, "which
nature has taught to all animals" [*Pandect. Just. I, tit. i], such as
sexual intercourse, education of offspring and so forth. Thirdly, there is in
man an inclination to good, according to the nature of his reason, which nature
is proper to him: thus man has a natural inclination to know the truth about
God, and to live in society: and in this respect, whatever pertains to this
inclination belongs to the natural law; for instance, to shun ignorance, to
avoid offending those among whom one has to live, and other such things regarding
the above inclination.
Reply to Objection
1. All these precepts of the law of nature have the
character of one natural law, inasmuch as they flow from one first precept.
Reply to Objection
2. All the inclinations of any parts whatsoever of human
nature, e.g. of the concupiscible and irascible parts, in so far as they are
ruled by reason, belong to the natural law, and are reduced to one first
precept, as stated above: so that the precepts of the natural law are many in
themselves, but are based on one common foundation.
Reply to Objection
3. Although reason is one in itself, yet it directs all
things regarding man; so that whatever can be ruled by reason, is contained
under the law of reason.
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Article 3. Whether all acts of virtue
are prescribed by the natural law
Objection 1. It would seem that
not all acts of virtue are prescribed by the natural law. Because, as stated
above (Q. 90, A. 2) it is essential to a law that it be ordained to the common
good. But some acts of virtue are ordained to the private good of the individual,
as is evident especially in regards to acts of temperance. Therefore not all
acts of virtue are the subject of natural law.
Objection 2. Further, every sin
is opposed to some virtuous act. If therefore all acts of virtue are prescribed
by the natural law, it seems to follow that all sins are against nature:
whereas this applies to certain special sins.
Objection 3. Further, those
things which are according to nature are common to all. But acts of virtue are
not common to all: since a thing is virtuous in one, and vicious in another.
Therefore not all acts of virtue are prescribed by the natural law.
On the contrary, Damascene says (De
Fide Orth. iii, 4) that "virtues are natural." Therefore virtuous
acts also are a subject of the natural law.
I answer that, We may speak of
virtuous acts in two ways: first, under the aspect of virtuous; secondly, as
such and such acts considered in their proper species. If then we speak of acts
of virtue, considered as virtuous, thus all virtuous acts belong to the natural
law. For it has been stated (A. 2) that to the natural law belongs everything
to which a man is inclined according to his nature. Now each thing is inclined
naturally to an operation that is suitable to it according to its form: thus
fire is inclined to give heat. Wherefore, since the rational soul is the proper
form of man, there is in every man a natural inclination to act according to
reason: and this is to act according to virtue. Consequently, considered thus,
all acts of virtue are prescribed by the natural law: since each one's reason
naturally dictates to him to act virtuously. But if we speak of virtuous acts,
considered in themselves, i.e. in their proper species, thus not all virtuous
acts are prescribed by the natural law: for many things are done virtuously, to
which nature does not incline at first; but which, through the inquiry of
reason, have been found by men to be conducive to well-living.
Reply to Objection
1. Temperance is about the natural concupiscences of food,
drink and sexual matters, which are indeed ordained to the natural common good,
just as other matters of law are ordained to the moral common good.
Reply to Objection
2. By human nature we may mean either that which is proper
to man─and in this sense all sins, as being against reason, are also against
nature, as Damascene states (De Fide Orth. ii, 30): or we may mean that nature
which is common to man and other animals; and in this sense, certain special
sins are said to be against nature; thus contrary to sexual intercourse, which
is natural to all animals, is unisexual lust, which has received the special
name of the unnatural crime.
Reply to Objection
3. This argument considers acts in themselves. For it is
owing to the various conditions of men, that certain acts are virtuous for
some, as being proportionate and becoming to them, while they are vicious for
others, as being out of proportion to them.
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Article 4. Whether the natural law is
the same in all men?
Objection 1. It would seem that
the natural law is not the same in all. For it is stated in the Decretals
(Dist. i) that "the natural law is that which is contained in the Law and
the Gospel." But this is not common to all men; because, as it is written
(Rom. 10:16), "all do not obey the gospel." Therefore the natural law
is not the same in all men.
Objection 2. Further,
"Things which are according to the law are said to be just," as
stated in Ethic. v. But it is stated in the same book that nothing is so universally
just as not to be subject to change in regard to some men. Therefore even the
natural law is not the same in all men.
Objection 3. Further, as stated
above (2, 3), to the natural law belongs everything to which a man is
inclined according to his nature. Now different men are naturally inclined to
different things; some to the desire of pleasures, others to the desire of
honors, and other men to other things. Therefore there is not one natural law
for all.
On the contrary, Isidore says
(Etym. v, 4): "The natural law is common to all nations."
I answer that, As stated above
(2, 3), to the natural law belongs those things to which a man is inclined
naturally: and among these it is proper to man to be inclined to act according
to reason. Now the process of reason is from the common to the proper, as
stated in Phys. i. The speculative reason, however, is differently situated in
this matter, from the practical reason. For, since the speculative reason is
busied chiefly with the necessary things, which cannot be otherwise than they
are, its proper conclusions, like the universal principles, contain the truth
without fail. The practical reason, on the other hand, is busied with
contingent matters, about which human actions are concerned: and consequently,
although there is necessity in the general principles, the more we descend to
matters of detail, the more frequently we encounter defects. Accordingly then
in speculative matters truth is the same in all men, both as to principles and
as to conclusions: although the truth is not known to all as regards the
conclusions, but only as regards the principles which are called common
notions. But in matters of action, truth or practical rectitude is not the same
for all, as to matters of detail, but only as to the general principles: and
where there is the same rectitude in matters of detail, it is not equally known
to all.
It is therefore
evident that, as regards the general principles whether of speculative or of
practical reason, truth or rectitude is the same for all, and is equally known
by all. As to the proper conclusions of the speculative reason, the truth is
the same for all, but is not equally known to all: thus it is true for all that
the three angles of a triangle are together equal to two right angles, although
it is not known to all. But as to the proper conclusions of the practical
reason, neither is the truth or rectitude the same for all, nor, where it is
the same, is it equally known by all. Thus it is right and true for all to act
according to reason: and from this principle it follows as a proper conclusion,
that goods entrusted to another should be restored to their owner. Now this is
true for the majority of cases: but it may happen in a particular case that it
would be injurious, and therefore unreasonable, to restore goods held in trust;
for instance, if they are claimed for the purpose of fighting against one's
country. And this principle will be found to fail the more, according as we
descend further into detail, e.g. if one were to say that goods held in trust
should be restored with such and such a guarantee, or in such and such a way;
because the greater the number of conditions added, the greater the number of
ways in which the principle may fail, so that it be not right to restore or not
to restore.
Consequently we
must say that the natural law, as to general principles, is the same for all,
both as to rectitude and as to knowledge. But as to certain matters of detail,
which are conclusions, as it were, of those general principles, it is the same
for all in the majority of cases, both as to rectitude and as to knowledge; and
yet in some few cases it may fail, both as to rectitude, by reason of certain
obstacles (just as natures subject to generation and corruption fail in some
few cases on account of some obstacle), and as to knowledge, since in some the
reason is perverted by passion, or evil habit, or an evil disposition of
nature; thus formerly, theft, although it is expressly contrary to the natural
law, was not considered wrong among the Germans, as Julius Caesar relates (De
Bello Gall. vi).
Reply to Objection
1. The meaning of the sentence quoted is not that whatever
is contained in the Law and the Gospel belongs to the natural law, since they
contain many things that are above nature; but that whatever belongs to the
natural law is fully contained in them. Wherefore Gratian, after saying that "the
natural law is what is contained in the Law and the Gospel," adds at once,
by way of example, "by which everyone is commanded to do to others as he
would be done by."
Reply to Objection
2. The saying of the Philosopher is to be understood of
things that are naturally just, not as general principles, but as conclusions
drawn from them, having rectitude in the majority of cases, but failing in a
few.
Reply to Objection
3. As, in man, reason rules and commands the other powers,
so all the natural inclinations belonging to the other powers must needs be
directed according to reason. Wherefore it is universally right for all men,
that all their inclinations should be directed according to reason.
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Article 5. Whether the natural law can
be changed?
Objection 1. It would seem that
the natural law can be changed. Because on Ecclus. 17:9, "He gave them
instructions, and the law of life," the gloss says: "He wished the
law of the letter to be written, in order to correct the law of nature."
But that which is corrected is changed. Therefore the natural law can be
changed.
Objection 2. Further, the
slaying of the innocent, adultery, and theft are against the natural law. But
we find these things changed by God: as when God commanded Abraham to slay his
innocent son (Gn. 22:2); and when he ordered the Jews to borrow and purloin the
vessels of the Egyptians (Ex. 12:35); and when He commanded Osee to take to
himself "a wife of fornications" (Osee 1:2). Therefore the natural
law can be changed.
Objection 3. Further, Isidore
says (Etym. 5:4) that "the possession of all things in common, and
universal freedom, are matters of natural law." But these things are seen
to be changed by human laws. Therefore it seems that the natural law is subject
to change.
On the contrary, It is said in the
Decretals (Dist. v): "The natural law dates from the creation of the
rational creature. It does not vary according to time, but remains
unchangeable."
I answer that, A change in the
natural law may be understood in two ways. First, by way of addition. In this
sense nothing hinders the natural law from being changed: since many things for
the benefit of human life have been added over and above the natural law, both
by the Divine law and by human laws.
Secondly, a change
in the natural law may be understood by way of subtraction, so that what
previously was according to the natural law, ceases to be so. In this sense,
the natural law is altogether unchangeable in its first principles: but in its
secondary principles, which, as we have said (A. 4), are certain detailed
proximate conclusions drawn from the first principles, the natural law is not
changed so that what it prescribes be not right in most cases. But it may be
changed in some particular cases of rare occurrence, through some special
causes hindering the observance of such precepts, as stated above (A. 4).
Reply to Objection
1. The written law is said to be given for the correction of
the natural law, either because it supplies what was wanting to the natural
law; or because the natural law was perverted in the hearts of some men, as to
certain matters, so that they esteemed those things good which are naturally
evil; which perversion stood in need of correction.
Reply to Objection
2. All men alike, both guilty and innocent, die the death of
nature: which death of nature is inflicted by the power of God on account of
original sin, according to 1 Kings 2:6: "The Lord killeth and maketh
alive." Consequently, by the command of God, death can be inflicted on any
man, guilty or innocent, without any injustice whatever. In like manner adultery
is intercourse with another's wife; who is allotted to him by the law emanating
from God. Consequently intercourse with any woman, by the command of God, is
neither adultery nor fornication. The same applies to theft, which is the
taking of another's property. For whatever is taken by the command of God, to
Whom all things belong, is not taken against the will of its owner, whereas it
is in this that theft consists. Nor is it only in human things, that whatever
is commanded by God is right; but also in natural things, whatever is done by
God, is, in some way, natural, as stated in the I, Q. 105, A. 6, ad 1.
Reply to Objection
3. A thing is said to belong to the natural law in two
ways. First, because nature inclines thereto: e.g. that one should not do harm
to another. Secondly, because nature did not bring in the contrary: thus we
might say that for man to be naked is of the natural law, because nature did
not give him clothes, but art invented them. In this sense, "the
possession of all things in common and universal freedom" are said to be
of the natural law, because, to wit, the distinction of possessions and slavery
were not brought in by nature, but devised by human reason for the benefit of
human life. Accordingly the law of nature was not changed in this respect,
except by addition.
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Article 6. Whether the law of nature
can be abolished from the heart of man?
Objection 1. It would seem that
the natural law can be abolished from the heart of man. Because on Rom. 2:14,
"When the Gentiles who have not the law," etc. a gloss says that
"the law of righteousness, which sin had blotted out, is graven on the
heart of man when he is restored by grace." But the law of righteousness
is the law of nature. Therefore the law of nature can be blotted out.
Objection 2. Further, the law
of grace is more efficacious than the law of nature. But the law of grace is
blotted out by sin. Much more therefore can the law of nature be blotted out.
Objection 3. Further, that
which is established by law is made just. But many things are enacted by men,
which are contrary to the law of nature. Therefore the law of nature can be
abolished from the heart of man.
On the contrary, Augustine says
(Confess. ii): "Thy law is written in the hearts of men, which iniquity
itself effaces not." But the law which is written in men's hearts is the
natural law. Therefore the natural law cannot be blotted out.
I answer that, As stated above
(4, 5), there belong to the natural law, first, certain most general
precepts, that are known to all; and secondly, certain secondary and more
detailed precepts, which are, as it were, conclusions following closely from
first principles. As to those general principles, the natural law, in the
abstract, can nowise be blotted out from men's hearts. But it is blotted out in
the case of a particular action, in so far as reason is hindered from applying
the general principle to a particular point of practice, on account of
concupiscence or some other passion, as stated above (Q. 77, A. 2). But as to
the other, i.e. the secondary precepts, the natural law can be blotted out from
the human heart, either by evil persuasions, just as in speculative matters
errors occur in respect of necessary conclusions; or by vicious customs and
corrupt habits, as among some men, theft, and even unnatural vices, as the
Apostle states (Rom. i), were not esteemed sinful.
Reply to Objection
1. Sin blots out the law of nature in particular cases, not
universally, except perchance in regard to the secondary precepts of the
natural law, in the way stated above.
Reply to Objection
2. Although grace is more efficacious than nature, yet
nature is more essential to man, and therefore more enduring.
Reply to Objection
3. This argument is true of the secondary precepts of the
natural law, against which some legislators have framed certain enactments
which are unjust.
