Natural Law Theories

Natural Law Theories

In General

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 (Finnis 2005/2011). 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 (or “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. 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, 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 2003). 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 2003 (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 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 questions, though organized and articulated a little differently, are under consideration in the present entry. [1]

Enabling positivity: social facts made reasons for action

The fulcrum and central question of natural law theories of law is: How and why can law, and its positing in legislation, judicial decisions, and customs, give its subjects sound reason for acting in accordance with it? How can a rule’s, a judgment’s, or an institution’s legal (“formal,” “systemic” ) validity, or its facticity or efficacy as a social phenomenon (e.g., of official practice), make it authoritative in its subject’s deliberations?

The sense and force of these questions, and the main features of the kind of answer given by natural law theories, can be given a preliminary indication. On the one hand, natural law theory holds that law’s “source-based character” -its dependence upon social facts such as legislation, custom or judicially established precedents-is a fundamental and primary element in “law’s capacity to advance the common good, to secure human rights, or to govern with integrity” (cf. Green 2003). On the other hand (again cf. Green 2003), the question “whether law is of its very nature morally problematic” has from the outset been the subject of consideration by leaders of the tradition. (The first issue that Aquinas takes up about human law in his set-piece discussion of law, Summa Theologiae, I-II, q. 95 a. 1, is whether human law [positive law] is beneficial-might we not do better with exhortations and warnings, or with judges appointed simply to “do justice” , or with wise leaders ruling as they see fit? …) Classic and leading contemporary texts of natural law theory treat law as morally problematic, understanding it as a normally indispensable instrument of great good but one that readily becomes an instrument of great evil unless its authors steadily and vigilantly make it good by recognizing and fulfilling their moral duties to do so, both in settling the content of its rules and principles and in the procedures and institutions by which they make and administer it. Natural law theories all understand law as a remedy against the great evils of, on the one side anarchy (lawlessness), and on the other side tyranny. And one of tyranny’s characteristic forms is the co-optation of law as a mask for fundamentally lawless decisions cloaked in the forms of law and legality. [2]

Review of Finnis Theories: The Basic Goods

Specific Criticisms of the Seven Goods

Finnis’s seven basic goods are:

  • Life
  • Knowledge
  • Play
  • Aesthetic Experience
  • Sociability
  • Practical Reasonableness
  • Religion

I think that positive emotion is a noticeable absentee here. The reason these seven goods are ‘basic’ is because they can be the foundation of an explanation, e.g. “why are you buying food?” “So I can eat” “Why do you want to eat?” “So I can stay alive” “Why do you want to stay alive?” “Because it is a basic good.” I think this kind of argument is perfectly acceptable if the last line is “because it makes me happy.”

Finnis argues that pleasure/pain are merely side effects of achieving/not achieving the basic goods, and anyone who pursues pleasure that is not associated with a basic good is living their life wrong. I think that this is dismissive of many valid life choices. Sometimes when people hear the word ‘pleasure’ and ‘pain’ they imagine shallow emotion, whereas I think ‘positive/negative emotion’ makes it clear that we can also talk about deep emotions like love, satisfaction from achievements, or grief.

This issue is tangential to a question of ‘what is law?’ so I’ll leave it here.

‘Aesthetic experience’

In a later revision, Finnis decided that ‘aesthetic experience’ could be subsumed under knowledge and play. He replaced it with a new basic good: “Marriage between man and woman for the purpose of having children.” It would be fun seeing what a legal theory class would make of that, and I don’t think I have any non-obvious criticisms of this good.

Things like this make it less likely that Finnis has correctly identified the basic goods. A stronger argument would be directed against the existence of any kind of basic good.

More General, Important Criticisms

Finnis’s Argument:

There are many principles of logic and science that have not been proved, such as ‘experience corresponds to reality’ or ‘modus ponens is a valid argument.’ He says that such arguments cannot be proved, but if we don’t assume them then we can’t get anywhere, so we have to assume them.
A basic good is the same. You cannot use facts like ‘This basic good seems good to me’, or ‘most people agree on the basic goods’ to prove the existence of a basic good – a basic good is unprovable. However, if you don’t accept the existence of basic goods, you cannot evaluate anything you do, or anything anyone else does, and you cannot make decisions for how to live your life. So you have to assume the basic goods.

My first objection is that principles that cannot be proven are not features of a scientific theory – they are problems. If someone finds a way to prove that experience corresponds to reality, everyone will be extremely pleased and will adjust their theories accordingly. Such a proof seems impossible to us, but that doesn’t mean it is impossible – we can do things today that would have seemed impossible to people even a hundred years ago, let alone 5’000. Science, maths and theoretical logic are making every effort to eliminate unprovable principles, with limited success (especially in the special sciences). So I don’t think Finnis can create unprovable principles in his own theory, and claim that this is ok because science and logic also do this.

Scientists and mathematicians also treat their assumptions differently. A scientists attitude to their assumptions is “I have made these assumptions. I must act as if they are true, because otherwise I couldn’t do anything. However, I acknowledge that my work may be useless if these assumptions turn out to be wrong. The assumptions seem to be working but hey, who knows, it’s just a model.” If you tried to transplant that attitude into Finnis’s basic goods, you would have to acknowledge that other people might construct moral theories with different assumptions, and then you’re left with Kelsen’s moral relativism.

Basic goods have three distinct properties:

  1. The basic goods explain human actions. An action is worthwhile if and only if it participates in a basic good.
  2. There is a single set of basic goods that applies equally to every society that ever has or ever will exist.
  3. The basic goods exist independent from our understanding of them.

Finnis’s argument as to why you should accept basic goods is that if you don’t, you won’t be able to evaluate anything morally. I think that you could grant this for property (1), however the other properties are not required to talk about morals. You could deny (2) by arguing that morals are different for different people, or at least different societies. Or you could argue that morals are common to all humans, but are still created by our understanding, and so accept (2) while denying (3).

These theories are not necessarily better than Finnis’s theory, but his argument – that you must accept that basic goods if you want to talk about morals – does not seem correct to me.


Finnis sets up a divide between the basic goods, which are objective, and morally correct courses of action, which are subjective. To build this divide he makes the following declaration: the basic goods cannot be compared with each other – there is no objective way to determine whether an act that pursues knowledge it better than an act that pursues life. Both are good actions, and it is up to us to choose which to pursue.

I have no strong arguments against this, but it feels wrong to me. It seems ‘obvious’ that some decisions are better than others in the same way that it’s ‘obvious’ that some decisions are good ideas in the first place. Finnis provides basic goods to explain the latter, but does nothing to explain the former. [3]




  1. Main source: Finnis, John, “Natural Law Theories”, The Stanford Encyclopedia of Philosophy (Fall 2011 Edition), Edward N. Zalta (ed.)
  2. Id.
  3. By Hugh McCarthy

See Also

Further Reading

Finnis, J. (2011, first published 1980). Natural law and natural rights. Oxford: Oxford University Press.



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