Natural Law Theories
First published Mon Feb 5, 2007; substantive revision Wed Jun 3, 2020
This entry considers natural law theories only as theories of law. That is not to say that legal
theory can be adequately identified and pursued independently of moral and political theory. Nor
is it to deny that there are worthwhile natural law theories much more concerned with
foundational issues in ethics and political theory than with law or legal theory. A sample of such
wider and more foundational theories is the entry Aquinas’ moral, political, and legal
philosophy. In the present entry, “natural law theory” is to be taken as shorthand for natural law
theories just insofar as they bear on law and are theories of or about it. This focus has the
important incidental effect that many historically important differences between natural law
theorists can be omitted, differences which pertain more to the foundations of normativity than to
the nature and functions (“the concept”) of positive law.
Legal theorists who present or understand their theories as “positivist”, or as instances of “legal
positivism”, take their theories to be opposed to, or at least clearly distinct from, natural law
theory. Natural law theorists, on the other hand, did not conceive their theories in opposition to,
or even as distinct from, legal positivism (contra Soper 1992 at 2395). The term “positive law”
was put into wide philosophical circulation first by Aquinas, and natural law theories of his kind
share, or at least make no effort to deny, many or virtually all “positivist” theses—except of
course the bare thesis that natural law theories are mistaken, or the thesis that a norm is the
content of an act of will. Natural law theory accepts that law can be considered and spoken
of both as a sheer social fact of power and practice, and as a set of reasons for action that can be
and often are sound as reasons and therefore normative for reasonable people addressed by them.
This dual character of positive law is presupposed by the well-known slogan “Unjust laws are
not laws.” Properly understood, that slogan indicates why—unless based upon some skeptical
denial that there are any sound reasons for action (a denial which can be set aside because
defending it is self-refuting)—positivist opposition to natural law theories is pointless, that is
redundant: what positivists characteristically see as realities to be affirmed are already affirmed
by natural law theory, and what they characteristically see as illusions to be dispelled are no part
of natural law theory. But because legal theories conceived of by their authors as positivist are,
1
,by and large, dominant in the milieux of those likely to be reading this entry, it seems
appropriate to refer to those theories along the way, in the hope of overcoming
misunderstandings that (while stimulating certain clarifications and improvements of natural law
theorizing) have generated some needless debate.
The point made in the preceding paragraph is made in another way by Orrego (Orrego 2007).
When the accounts of adjudication and judicial reasoning proposed by contemporary mainstream
legal theories are added to those theories’ accounts of (the concept of) law, it becomes clear that,
at the level of propositions (as distinct from names, words and formulations), those theories share
(though not always without self-contradiction) the principal theses about law which are proposed
by classic natural law theorists such as Aquinas: (i) that law establishes reasons for action, (ii)
that its rules can and presumptively (defeasibly) do create moral obligations that did not as such
exist prior to the positing of the rules, (iii) that that kind of legal-moral obligation is defeated by
a posited rule’s serious immorality (injustice), and (iv) that judicial and other paradigmatically
legal deliberation, reasoning and judgment includes, concurrently, both natural (moral) law and
(purely) positive law. Orrego’s point seems to be confirmed by, e.g., the adjacent entry on Legal
Positivism (Green and Adams 2019). Contemporary “positivist” theories are, it seems, natural
law theories, distinguished from the main body of natural law theory (a) by their denial that the
theory of law (as distinct from the theory or theories of adjudication, judicial duty, citizens’
allegiance, etc.) necessarily or most appropriately tackles the related matters just listed, and
accordingly (b) by the incompleteness of their theories of law, that is, the absence from them
(and usually, though not always, from their accounts of those related matters) of systematic
critical attention to the foundations of the moral and other normative claims that they make or
presuppose.
In short: a natural law theory of (the nature of) law seeks both to give an account of the facticity
of law and to answer questions that remain central to understanding law. As listed by Green 2019
(having observed that “No legal philosopher can be only a legal positivist”), these further
questions (which “legal positivism does not aspire to answer”) are: What kinds of things could
possibly count as the merits of law? What role should law play in adjudication? What claim has
law on our obedience? What laws should we have? And should we have law at all? All these
2
, questions, though organized and articulated a little differently, are under consideration in the
present entry.
1. Enabling positivity: social facts made reasons for action
o 1.1 Basic reasons for action and the need for governmental authority
o 1.2 Political authority as remedy for anarchy, injustice and impoverishment
o 1.3 Rule of law as remedy for the dangers in having rulers
o 1.4 Ius gentium—ius cogens—mala in se—human rights: legal rules and rights
posited because morally necessary parts of any legal system
o 1.5 “Purely positive law”: determinationes and their legal-moral authority for
citizens and judges (facts made reasons for action)
2. Human persons are not law’s creatures but its proper point
3. Legal principles to remedy defective positive law
o 3.1 Adjudicating between exclusive and inclusive legal positivism
o 3.2 Natural law and (purely) positive law as concurrent dimensions of legal
reasoning
o 3.3 Implications of the rule-of-law need for positivity
4. “Lex iniusta non est lex”? Do seriously unjust laws bind? Legally?
5. Can general theories of law be value-free? moral-value-free?
6. Other elements of natural law theory
o 6.1 Intention in action and utterance
o 6.2 Responsibility and punishment
o 6.3 Each legal system is of and for a particular political community
Bibliography
Academic Tools
Other Internet Resources
3
First published Mon Feb 5, 2007; substantive revision Wed Jun 3, 2020
This entry considers natural law theories only as theories of law. That is not to say that legal
theory can be adequately identified and pursued independently of moral and political theory. Nor
is it to deny that there are worthwhile natural law theories much more concerned with
foundational issues in ethics and political theory than with law or legal theory. A sample of such
wider and more foundational theories is the entry Aquinas’ moral, political, and legal
philosophy. In the present entry, “natural law theory” is to be taken as shorthand for natural law
theories just insofar as they bear on law and are theories of or about it. This focus has the
important incidental effect that many historically important differences between natural law
theorists can be omitted, differences which pertain more to the foundations of normativity than to
the nature and functions (“the concept”) of positive law.
Legal theorists who present or understand their theories as “positivist”, or as instances of “legal
positivism”, take their theories to be opposed to, or at least clearly distinct from, natural law
theory. Natural law theorists, on the other hand, did not conceive their theories in opposition to,
or even as distinct from, legal positivism (contra Soper 1992 at 2395). The term “positive law”
was put into wide philosophical circulation first by Aquinas, and natural law theories of his kind
share, or at least make no effort to deny, many or virtually all “positivist” theses—except of
course the bare thesis that natural law theories are mistaken, or the thesis that a norm is the
content of an act of will. Natural law theory accepts that law can be considered and spoken
of both as a sheer social fact of power and practice, and as a set of reasons for action that can be
and often are sound as reasons and therefore normative for reasonable people addressed by them.
This dual character of positive law is presupposed by the well-known slogan “Unjust laws are
not laws.” Properly understood, that slogan indicates why—unless based upon some skeptical
denial that there are any sound reasons for action (a denial which can be set aside because
defending it is self-refuting)—positivist opposition to natural law theories is pointless, that is
redundant: what positivists characteristically see as realities to be affirmed are already affirmed
by natural law theory, and what they characteristically see as illusions to be dispelled are no part
of natural law theory. But because legal theories conceived of by their authors as positivist are,
1
,by and large, dominant in the milieux of those likely to be reading this entry, it seems
appropriate to refer to those theories along the way, in the hope of overcoming
misunderstandings that (while stimulating certain clarifications and improvements of natural law
theorizing) have generated some needless debate.
The point made in the preceding paragraph is made in another way by Orrego (Orrego 2007).
When the accounts of adjudication and judicial reasoning proposed by contemporary mainstream
legal theories are added to those theories’ accounts of (the concept of) law, it becomes clear that,
at the level of propositions (as distinct from names, words and formulations), those theories share
(though not always without self-contradiction) the principal theses about law which are proposed
by classic natural law theorists such as Aquinas: (i) that law establishes reasons for action, (ii)
that its rules can and presumptively (defeasibly) do create moral obligations that did not as such
exist prior to the positing of the rules, (iii) that that kind of legal-moral obligation is defeated by
a posited rule’s serious immorality (injustice), and (iv) that judicial and other paradigmatically
legal deliberation, reasoning and judgment includes, concurrently, both natural (moral) law and
(purely) positive law. Orrego’s point seems to be confirmed by, e.g., the adjacent entry on Legal
Positivism (Green and Adams 2019). Contemporary “positivist” theories are, it seems, natural
law theories, distinguished from the main body of natural law theory (a) by their denial that the
theory of law (as distinct from the theory or theories of adjudication, judicial duty, citizens’
allegiance, etc.) necessarily or most appropriately tackles the related matters just listed, and
accordingly (b) by the incompleteness of their theories of law, that is, the absence from them
(and usually, though not always, from their accounts of those related matters) of systematic
critical attention to the foundations of the moral and other normative claims that they make or
presuppose.
In short: a natural law theory of (the nature of) law seeks both to give an account of the facticity
of law and to answer questions that remain central to understanding law. As listed by Green 2019
(having observed that “No legal philosopher can be only a legal positivist”), these further
questions (which “legal positivism does not aspire to answer”) are: What kinds of things could
possibly count as the merits of law? What role should law play in adjudication? What claim has
law on our obedience? What laws should we have? And should we have law at all? All these
2
, questions, though organized and articulated a little differently, are under consideration in the
present entry.
1. Enabling positivity: social facts made reasons for action
o 1.1 Basic reasons for action and the need for governmental authority
o 1.2 Political authority as remedy for anarchy, injustice and impoverishment
o 1.3 Rule of law as remedy for the dangers in having rulers
o 1.4 Ius gentium—ius cogens—mala in se—human rights: legal rules and rights
posited because morally necessary parts of any legal system
o 1.5 “Purely positive law”: determinationes and their legal-moral authority for
citizens and judges (facts made reasons for action)
2. Human persons are not law’s creatures but its proper point
3. Legal principles to remedy defective positive law
o 3.1 Adjudicating between exclusive and inclusive legal positivism
o 3.2 Natural law and (purely) positive law as concurrent dimensions of legal
reasoning
o 3.3 Implications of the rule-of-law need for positivity
4. “Lex iniusta non est lex”? Do seriously unjust laws bind? Legally?
5. Can general theories of law be value-free? moral-value-free?
6. Other elements of natural law theory
o 6.1 Intention in action and utterance
o 6.2 Responsibility and punishment
o 6.3 Each legal system is of and for a particular political community
Bibliography
Academic Tools
Other Internet Resources
3
