Sometimes I hear arguments that seem to appeal to the fact that something is morally permissible because it is legally permitted. For example:

  • Abortion is moral because it's legally permitted. Killing two year olds is immoral because we have laws against it.
  • Putting your money into offshore bank accounts to avoid taxes is perfectly legal, thus I see nothing morally wrong with it.
  • The law allows me to keep a slave, therefore it is my moral right to do so.

This appears to be fallacious, since there are cases where modern people assert that something is immoral that was historically legal (e.g. chattel slavery), thus something can still be legal yet immoral. Nonetheless, this belief seems to persist.

Is there a term for this belief that "if it's legal, it's moral", either as a name for a fallacious argument or as a name for a philosophical belief? Let's assume we are talking about laws that are made by people, rather than by nature (i.e. natural law) or by God (i.e. divine law).

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    Is it the idea that "if it is legal, then it must be moral in some way", or "there is only one moral duty: follow the laws of society, whatever it may be" ? While leading to the same result, both have very different premises.
    – armand
    Commented Jun 17, 2019 at 0:51
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    Some shorten it to "legal makes moral". But the motto leads to so much nonsense so quickly (especially if no basis is given to how the laws come to be laid down) that no serious thinker defended it. The closest I can think of is legal moralism, but it still bases legal on "society's collective moral judgments".
    – Conifold
    Commented Jun 17, 2019 at 5:55
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    I understand the point behind "This appears to be fallacious, since there are cases where modern people assert that something is immoral that was historically legal (e.g. chattel slavery), thus something can still be legal yet immoral.", but that argument also highlights the unstated premise that what is moral and immoral does not change over time or in situations, with which some ethical theories would disagree. Commented Jun 17, 2019 at 11:54
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    Your examples are odd. Personally I’ve never heard your first or third example, although I accept that the third might have existed in the past. Similarly, offshore banking itself is obviously not a problem, but the morally objectionable form of it — hidden offshore bank accounts that you don’t pay taxes on — is also usually illegal. Do you have a better example, or can you justify why you picked these (to my mind) odd examples? Commented Jun 17, 2019 at 12:35
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    I think you mean "we are talking about laws that are made by people". The question does also lead to the problematic question of "what is moral?" God is by His own admission not moral, as amply demonstrated by the Old Testament. "Natural law" tends to rely largely on the "ick" response which for most people has large inconsistencies when you start digging. Humanism is the best we can do, as demonstrated by wholesale rejection of Old Testament rules (when did you last kill someone for wearing mixed fibres, for example?), but tends not to give absolute answers.
    – Graham
    Commented Jun 17, 2019 at 13:50

6 Answers 6


We are talking about "Appeal to law" fallacy.

When following the law is assumed to be the morally correct thing to do, without justification, or when breaking the law is assumed to be the morally wrong thing to do, without justification.

It could also be taken as special form of appeal to authority or argumentum ad verecundiam fallacy, in which the authority that which is appealed to is laws of the land. Basically, the argument goes that laws are minimum agreed upon by society moral rules in the land. Therefore, by claiming that behavior is moral thanks to the laws, the person is making an argument in which the ultimate authority of moral behavior is group making and enforcing the laws.

For the person who unflinchingly obeys laws despite that behavior not making sense in the situation or not being "good", the term used is Lawful Stupid. Edit: Warning, Lawful Stupid is tvtropes link!

  • It can be an appeal to the law in case it is used in a context where two parties are arguing about a legal and ethical topic. But, in general if you adopt the view that something is legal because there is some moral reason for that, then that's legal interpretivism
    – SmootQ
    Commented Jun 17, 2019 at 18:19
  • And if we were to argue about something it would be fallacious to say that it is moral since it is legal. Otherwise it is still possible to agree that everything that is legal is based on morality and call ourselves legal interpretivists. So it is okay to think that legal is base on moral, but it is not okay to think that you can use that claim in arguments if the other party does not hold such claim.
    – SmootQ
    Commented Jun 17, 2019 at 18:21
  • @jo1storm "... appeal to authority ..." -> but, beware the "appeal to authority fallacy fallacy" :-). Which is somewhat covered in the authority you cite :-). Commented Jun 18, 2019 at 11:07
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    @Davor - Interesting, thanks, that helps to understand where you're coming from. In the framework you accept, what would be the process of deciding whether a particular thing would become law or not? I guess, can you pick an example, like slavery, and explore what the process of deciding whether to make a law prohibiting it or not? That is, what factors would be considered and why. It seems we should be moving this to chat now, actually, based on the SO guidance. Commented Jun 18, 2019 at 15:39
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    @DonBranson - Really, this is how lawful good work in DnD. Paladins are religious and lawful zealots, if law says "gas the jews", than that must be the right thing to do in their view. Plenty of atrocities (in my and your opinion) were committed by people believing themselves right. Even frickin Hitler believed he was removing the dangers to his people.
    – Davor
    Commented Jun 19, 2019 at 9:21

I think what you are looking for is called Legal Interpretivism, which, unlike Legal Positivism (which asserts that laws are distinct from morality), asserts that laws are based on morality, and that there is no separation between law and morality, so there must be an interpretation for why such and such is legal or illegal.

In which case, the statement if it is legal then there must be moral reason for it to be legal would hold true, only if you consider an interpretivist point of view.

Interpretation is a kind of moral processing of these norms. To interpret is to assess the norms constituted by institutional communication and adjust the set in order to make it more attractive in some way

That is, to tweak and play with one's understanding of the laws, then interpret those laws in order for them to match some moral preferences, for example: Abortion is legal, and it is totally moral because women are free and have the right to their bodies, and you cannot kill a kid who was never born, so that must be the reason why it is legal.

(and if it is illegal, a legal interpretivist would give a moral reason why it is illegal).

Third, for interpretivism, the justifying role of principles is fundamental: for any legal right or obligation, some moral principles ultimately explain how it is that institutional and other nonmoral considerations have roles as determinants of the right or obligation. In the order of explanation, morality comes first.


Of course there are other points which set Legal Interpretivism apart from Legal Positivism and Natural Law Theory...etc.

Caveat: Is it an appeal to authority (law) fallacy?

It is important to know when we say that such and such is a fallacy. A statement or assertion cannot be a fallacy, if I say: If x is legal then x is Moral, this is a claim, not a fallacy.

That is, I claim that such and such is the case, that it matches some state of affairs in the actual world.

And when arguing with others, I can use that statement as a premise. And the other party can check whether my argument is valid or not.

  • Premise 1: For all x, If x is legal then x must be moral
  • Premise 2: Abortion is legal.
  • Conclusion: therefore, Abortion must be moral.

The other party would not argue about the validity of the argument, that argument is certainly valid and not fallacious.

What remains is whether the other party accepts the premises as true.

Whether they do or do not accept the first premise is not a fallacy, you believe that the conditional is true and they believe it is false. In either case, the one who accepts the first conditional as true is a Legal Interpretivist.

But suppose two people are involved in a serious discussion about the subject, not just formal deductive arguments:

  • A: Abortion is moral.
  • B: Can you give me a good inductive or deductive argument as to why you think so?
  • A: Because the law says so, and you have to accept it.
  • B: mmm... okay!

Here, this is an informal fallacy (Appeal to the authority of the law), simply because A did not state the reason why they think so.

It is a fallacy A did not take much time to formulate an argument and ask whether B agrees with the premises or not, they just presuppose that the fact that Law says so then B must also agree with it, which is an appeal to authority.

  • So is legal interpretivism a form of apologetics, where the goal is to justify laws (whatever they might happen to be) by reference to moral principles?
    – ruakh
    Commented Jun 17, 2019 at 18:21
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    In general, philosophical positions are claims, assertions or sets of claims and assertions. That can be used as premises if the two arguing parties agree with those premises. Otherwise it would be useless to argue with a legal positivist that abortion is legal because it is moral since a legal positivist would not accept that premise. So it is not for apologetics to use against those who do not agree. It is to use in the philosophy of law and not in general arguments. I would be a fool if I were to use an interpretivist argument against someone who is not an interpretivist.
    – SmootQ
    Commented Jun 17, 2019 at 18:30
  • I added a caveat to the answer : is it a fallacy of appeal to authority or not?
    – SmootQ
    Commented Jun 20, 2019 at 9:40

In a democracy, I don't think this is an appeal to authority anymore, nor is it entirely circular.

It is clear that laws are based upon the shared moral sentiments of the population, if we are electing our legislators and even our judges. They have authority, but it is our authority.

We may not feel represented by the composite, here, in the same way that the current form of the English language may not be the language we would choose to have, and we might disown, disparage, or ignore parts. But despite the unequal representation, various power relations and affordances to our own weaknesses and external pressures that any social compositing process involves, the rules our society in general enforces are our composite moral sentiments. We control them and they are built out of our coordinated decisions. We change them by winning or losing arguments about what is right, and they have no other source material, absent some outside antidemocratic force. (Capitalism does not really qualify, it is hardly 'outside').

The dark forces that shape our politics and form the worst aspects of our laws are just parts of our morality that we would rather not discuss. The analogy with language as a similar form of social construct holds: For instance, we have a language that chooses given forms of sex which are presumed to be unwanted as the primary metaphor for advantage-taking, lack of consideration, and bad luck. And that does represent a dominant culturally shared opinion of the people who take the roles alluded to in those metaphors. I may find sucking and being screwed to be glorious opportunities worth seeking after, and so might a whole lot of women, but we in the composite, as a culture do not wholly approve. We can then claim the culture really agrees with us, because we are on the more 'speakable' side of the issue right now. But when we do, we know we are lying. Otherwise, our shared aversion would change the language over time.

Then isn't this sentiment just the fallacy of affirming the consequent? Laws represent our shared sense of order, including large parts of our composite morality. So to take them as determining morality is following the implication of the definitions involved in the wrong direction.

However, one can follow any induction backward correctly in the negative, and there is neither a philosophical position, nor a fallacy involved. So it really depends upon whether you are arguing a necessary or a sufficient position, and where the negations of principles fall.

You cannot determine that an act is moral from the law, but you can deduce that many are morally compromised. You can deduce, for instance, that unexpectedly violating the laws protecting other people, based on your own personal decisions, is at least partly immoral. People have entered into the institution of citizenship (voluntarily or otherwise) primarily for the purpose of stability, and you are depriving them of that stability. Unless you forfeit all the associated privileges, you are acting destructively and in bad faith. (Exceptions apply, but the argument, as far as it goes without falling prey to other issues, has some real moral force.)

Appeals to authority and other circular arguments do not have this feature of having real applicability in one direction, but not in the other.

  • "[In a democracy] it is clear that laws are based upon the shared moral sentiments of the population, if we are electing our legislators" - I don't agree that this is clear. In a democracy, laws are based on the shared desires of the population, not the shared moral sentiments. Perhaps some people desire what they think is moral, and perhaps others desire what they don't think is moral. The point is that morality is not a prerequisite to democratic participation, and a democratic outcome says nothing about the morality of that outcome.
    – JBentley
    Commented Jun 19, 2019 at 20:15
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    That seems a bit idealistic, to be charitable. Democracies are not perfect (and are not actually democracies, most of the time) and laws are not morals. Some laws have moral underpinnings, but it's not necessarily the case. And if you've followed US politics for any length of time you'd be aware of many laws that the majority hate, or that the majority supported but were removed.
    – Harabeck
    Commented Jun 19, 2019 at 20:17
  • This is surely not idealism. It presents a very dark view of most people's real morality, built mostly of lies. An interactive process just does not let us lie as readily. I have edited this argument in, to avoid having this discussion a third time.
    – user9166
    Commented Jun 21, 2019 at 0:45
  • As many drug-dealers are now discovering, you may disapprove of a law in principle, but in fact rely upon it in every way, and when it really comes time to change things, you may find that you really approved all along.
    – user9166
    Commented Jun 21, 2019 at 1:42

From our western perspective, it certainly is an "Appeal to Law" fallacy and @jo1storm's answer deserves all the upvotes.

In the West, with the notable partial exceptions of Machiavelli and Hobbes, the thoughtful kids have pretty much assumed―at least since Euthyphro came out―that true morality must be prior and superior to any lawgiver up to and including the gods. Anyone attempting to end a moral argument (in good faith) on an appeal to divine authority can be run through Socrates's questions until they realize their mistake; anyone attempting the same tack with an appeal to human lawgivers is going to hit the rocks even sooner.

Since no one else has mentioned it yet, though, yes, there is a philosophical system that upholds the will of rulers as the actual criterion of morality. It's

Legalism (法家, Fǎjiā),

the philosophical school most associated with Han Fei, his eponymous text, and the First Emperor.

It's more nuanced and particularly Chinese in the details, but the short version is that the emperor gets what he wants and the proper thing for any subject to do in any situation is to obey. The Han subsequently overlaid this with a return to dynastic feudalism and an official endorsement of Confucianism, which came with a whole host of obligations and a higher morality that establishes who's ruling justly and who's a tyrant. In practice, any time the scholars tried to uphold those ideals on a serious point (e.g. Zhu Di's usurpation of his young nephew during the early Ming Dynasty), the scholars and everyone they knew were tortured and/or executed until everyone fell in line behind the emperor's will.

  • What you described is still an appeal to authority. It is not a philosophical system. It expresses whoever is in charge must be correct or else . . .
    – Logikal
    Commented Jun 19, 2019 at 20:36
  • It's not an appeal to authority in the conventional sense. As described, it's perhapse more Argumentum ad baculum (en.wikipedia.org/wiki/Argumentum_ad_baculum)
    – Josiah
    Commented Jun 19, 2019 at 20:55
  • @Logikal It certainly is a philosophical system. You may very much dislike its premises and results, but that doesn't make Chinese philosophy "failed" Western thought... and you should be aware of the very unpleasant history associated with people whose thought did tend that way...
    – lly
    Commented Jun 21, 2019 at 14:21
  • @Logikal Comparing others to animals and claiming that they are the ones misunderstanding and misusing terms in a "common" way is preternaturally offensive, regardless of the preface you attach to your words. Beyond which, you remain both mistaken and highly blinkered: legalism remains an actual ethnical system, not a logical or conceptual error of Western philosophy.
    – lly
    Commented Jun 21, 2019 at 16:04

As earlier posters have said, it can be interpreted as an appeal to authority (the law). Fundamentally, it is a form of circular reasoning based on the premise that all laws are moral:

  1. The law is moral
  2. The law allows for X
  3. X is moral
  • I take your point, but your current argument is just a syllogism and not actually circular reasoning. You're assuming that your own axiom is false, but that's not necessarily so.
    – lly
    Commented Jun 19, 2019 at 18:58

It seems that this is too varied a position to pin a single label on.

One label would be "conventional" or "Law and order" morality, as used in Kohlberg's stages of moral development. It's worth noting that this is not a prescriptive theory by an ethicist about how people should think or behave, but a descriptivist theory by a psychologist about how they do. In summary, the claim is that most people defer moral reasoning to some sort of outside societal consensus, one example of which could be a codified law.

Again reaching away from philosophy and toward sociologists, Haidt et al's Moral foundations theory suggests that most people's moral reasoning rests on some subset of six abstract principles: Care, Fairness, Loyalty, Authority, Sanctity and Liberty. Without looking into why these abstract principles are considered foundations for morality, some of these lend some support to a "legal implies moral" claim: liberty, authority, and fairness most obviously.

A "Liberty" foundation echoes strongly with the legal principle "Everything which is not forbidden is allowed." That is, human freedom is respected by default, and there is a deep suspicion of any claims that would curtail it.

"Authority" does not have quite the same sense as in "appeal to authority", in which the "authority" is assumed to know better. It is more a morality of deference. The authority defines better. This does not actually need the source of law to be unchanging or necessarily even "right". If your law-giver declares a hose-pipe ban, it would be subversive to water your garden with a hose pipe. If they then lift that ban, it would not.

"Fairness" perhaps wants the most exposition: the argument would be that the law provides fairness by defining the constraints for everyone. Interestingly, this also allows for a model that there could be a changeable or bad law, which individual morality is still bound or released by. For example, I might believe in the abstract that a society which curtailed advertising would be better off; I might even want to push for laws restricting advertising. At the same time as a business owner in a society that does not curtail advertising, I might feel released to advertise as hard as I can, so as to compete on a level field with the rest of my industry. For a second example, consider the many pro-gun arguments (mostly in the USA) that have the basic form "If the bad guys have guns, the good guys should too."

Moving away from Haidt, perhaps a rule consequentialist could decide that "Just follow the law of the land" is a good rule for the typical non-expert to practically maximise utility. This almost swings back to Kohlberg's conventionalism, but it's actually a higher level. Such a person is not just defering to society because it's never occured to them to think for themselves. Instead they have explored broader principles, recognised their own human falibility, and chosen to defer where that is likely better than trying to figure things out for themselves. If anything, such a person is more likely to to see codified law as something thought through by relative experts, and be less likely to see accidental consensus about etiquette or such as binding.

There are other ways that one could arrive at "legal implies morally permissible" from other moral frameworks. My purpose here was just to illustrate some of the diversity.

The question that remains is "is it a fallacy?" That is going to depend on what is actually being argued. Most of my suggested mechanisms would make it understandable that someone would go to it as a useful heuristic for what they should do in a moment. As with all heuristics, it would still remain defeasible. To reiterate, Kohlberg's theory is descriptive rather than normative, but it does leave room for progressing to the next stage and reasoning more abstractly. Haidt's foundations are mutually intertwined, so a liberty foundation might nevertheless be trumped by a care foundation. Rule consequentialism could maintain deference to society's experts in general, while following ones' own rules on some issues which one has taken the time to evaluate.

It would probably be suboptimal to take the principle for individual decisions in which there is sufficient time to work through other morally relevant considerations. It is almost† certainly be fallacious to take the principle not for individual decisions but for guiding what society's laws should be. That would indeed be circular reasoning.

† almost because time delays can break the circle. Precedent based legal systems work with this and are not circular: instead of "it's legal because it's legal" they say "it's (il)legal today because it was (il)legal yesterday". They tend to lean heavily on notions of "fairness" too: it would be unfair if the same action was punished in one case and not the other. But sane legal systems will have some form of mind change release valve to avoid the obvious sunk cost fallacy, and that release valve will require moral reasoning other than "it was legal yesterday."

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