Should Incest be Decriminalised? (Part Three)

(Part One, Part Two)

This is third post in a brief series looking at the ethics of incest, specifically at whether incest should be decriminalised. Making use of Vera Bergelson’s article — “Vice is Nice but Incest is Best” — the series is examining the arguments traditionally used to support criminalisation.


So far, we’ve looked at four different arguments. In part one, we looked at arguments based on universal tradition and religious authority. We found both to be lacking. In part two, we looked at arguments from genetic defectiveness and disruption of the family unit. Although popular, and oft-cited as the primary reasons for criminalising the practice, both arguments were deemed to be flawed.

In this post we’ll look at two more arguments. The first is the argument from the prevention of sexual abuse; the second is the argument from immorality and offensiveness. We will also conclude by briefly considering the likely effects of decriminalising incest.


1. The Argument from the Prevention of Sexual Abuse
This argument is neither persuasive nor philosophically interesting, but it is surprisingly pervasive so we need to give it some consideration. The argument claims that incest laws are needed in order to prevent sexual abuse within families. One can understand the concern. Children and dependent family members are often abused by older siblings and parents so anything that can help to prevent this kind of abuse from occurring is to be welcomed.

Although the concern is understandable, is the claim made on behalf of incest laws a good one? To answer that, let’s first formalise the argument:

• (1) If an activity constitutes a form sexual abuse and domination, it ought to be criminalised. 

• (2) Incest constitutes a form of sexual abuse or domination.

• (3) Therefore, incest ought to be criminalised.

As I say, the general principle stated by premise (1) looks pretty sound to me. But the claim made by premise (2) seems deeply flawed. Most importantly, as specifically defined in the first part of this series, incest involves consensual sexual relations between adult relatives. As such it is not a form of abuse or domination. This definition is mirrored in most incest statutes, which typically ban all consensual sexual relations between close relatives and ban marriages between such relatives too. So, in other words, those laws do not limit themselves to abusive relationships.

Of course, that’s not to say that abuse or domination do not take place within families or that we should do nothing about it. But this brings us to the second point: there are plenty of other laws on the books that cover abuse and sexual domination within families. Looking solely to the legal position in England and Wales, we find that sections 5-8 of the Sexual Offences Act 2003 make it an offence to engage in or incite sexual activity with children under the age of 13, irrespective of whether they consent (because, broadly speaking, children below that aged are deemed incapable of consenting to such activities). These laws would cover the kind of scenario envisaged by this particular defence of incest laws thus rendering specific incest laws redundant.


2. Arguments from Immorality and Offence
The final argument in favour of the criminalisation of incest may be called the argument from immorality and offensiveness. Although I am fan of linguistic purity in matters philosophical — and although I personally think it best not to conflate “immorality” and “offensiveness” — I break my own rules here in the interests of legal-historical accuracy. Debates about so-called “morals legislation” have been common in the law for a long time, and within those debates one often finds the concept of immorality being deployed coextensively with the concept of offensive conduct.

Perhaps the best example of this comes from the famous Hart-Devlin debate on the decriminalisation of homosexuality. In the 1950s, the Wolfenden Committee wrote a report calling for the decriminalisation of homosexual conduct in England and Wales. This was partly on the grounds that such conduct was a matter of private “morality”, and not something for legal system to get involved in.

Patrick Devlin, a well-known law lord in the mid-20th century, wrote a response to the Wolfenden Committee’s report, arguing that the legal system could justifiably involve itself in such matters of private morality. He claimed that societies tend to disintegrate when people stop following a common moral code and hence, if homosexuality is a “vice so abominable that its mere presence is an offence” to that code it ought to be criminalised. HLA Hart, the Oxford don and legal philosopher, replied in fairly standard liberal form by arguing that the law should only get involved when a practice had some demonstrably harmful effect, or violated somebody’s autonomy, of which homosexuality did neither.

Devlin’s position is effectively a form of populism not moralism. It calls for legal rules to track the moral opinions of the majority of people. If conduct is deemed offensive or abominable by that majority, then we ought to criminalise it, irrespective of whether it breaches some acceptable moral principle. I’ve always found it odd that this has been termed “moralism” by many writers in this area, but that’s the term that has stuck.

Devlin’s argument can of course be co-opted in order to defend the criminalisation of incest. As follows:

• (4) If a type of conduct is deemed deeply offensive by the (vast) majority of society, it ought to be criminalised. 

• (5) Incest is deemed deeply offensive by the vast majority of society. 

• (6) Therefore, incest ought to be criminalised.

Marking something of a change from the previous arguments, the second premise of this one (premise (5)) looks like it is actually true. Most people do express extreme disgust and revulsion at the notion of incest, one can assume therefore that they do find it to be deeply offensive.

The problem is that it is not clear that offensiveness is a good ground for criminalisation. Indeed, the very fact that similar grounds have been invoked in order to outlaw practices we now deem morally acceptable (including homosexuality, and mixed-race marriages) or to demonise certain members of society (including Blacks and Jews) suggests we’d be on very shaky ground if we used such a principle.

In their recent work on the principles of criminalisation, Simester and von Hirsch, argue that the offence principle is unlikely to be morally sufficient to criminalise some form of conduct unless that conduct also has an obviously harmful aspect to it. Consensual sexual relationships between adult close relatives do not seem to have such an aspect, as we have seen elsewhere in this series, so there would appear to be no good grounds for criminalising it.


3. Conclusion
Following Bergelson’s work, this series has explored the traditional rationales for the criminalisation of incest. As we have seen, none of these rationales is particularly persuasive. The arguments from universal tradition and religious authority assign inappropriate moral weight to both. The argument from genetic defectiveness fails to justify all aspects of typical incest statutes and would outlaw other sexual unions that people find morally acceptable. The argument from protection of the family unit fails to account for the criminalisation of adult consensual incest and for the non-criminalisation of other activities that might undermine the family unit. The argument from the prevention of abuse is redundant since other laws cover abusive intra-familial relationships, and the argument from immorality and offensiveness is unmerited in a liberal society.

That seems to lead to the conclusion that incest ought to be decriminalised. As I noted in part one, this simply means that punitive sanctions should no longer be imposed upon those who engage in it. That does not mean that incest ought to be endorsed or encouraged. Indeed, as Bergelson notes at the end of her article, the very fact that so many people find incest to be repugnant makes it unlikely that decriminalisation would have this effect. The taboo against incest seems to be deeply engrained, with a strong biological and developmental component (the so-called Westermarck effect), thus its decriminalisation is unlikely to have a serious effect.