This post follows on from here.
Consider a society in which adultery is legal (most liberal democracies, in fact), and compare this to a society in which it is not. To avoid complicated definitions and legal potholes, I will use the term ‘adultery’ in this context to refer to dishonest ‘cheating’ on one person in a romantic relationship (not necessarily marriage) by the other. Now, in the latter society, while it is unlikely that adultery will be eliminated by its prohibition, if adultery was penalized with a short jail term or fine then we can reasonably suppose that there will be fewer instances of adultery than there would be in the former society. What is it about adultery that means that; although we think it to be immoral we are willing for it to remain legal?
We might start by saying that the dropping of litter affects the public, i.e. those that visit the public area in question. They have to put up with a dirty and less aesthetically pleasing visible environment, and so those that drop litter on the ground ruin the scenery for everybody else. Adultery is a private affair, and only those directly involved (i.e. the victim) are negatively affected. This does not seem to me to be the relevant distinction. There are other acts like theft and homicide that do not affect the wider public, and these are rightly prohibited by the state. Adultery may be a private affair, but this does not necessarily mean that those involved are capable of sorting it out themselves in a reasonable way – they may wish for protection by the state against being cheated on, in the same way we require laws against homicide to protect us from being purposefully killed by another person.
Another possibility is that someone might have a good reason to commit adultery, due to an abusive husband or concerns about ‘family honour’ or tradition. It might therefore be the case that a secret relationship is the only way to prevent more serious repercussions like domestic abuse or, worse still, ‘honour killing’. If adultery was outlawed, people in these sorts of situations would be forced by the state to remain loyal to a partner undeserving of such loyalty. Could it be that the fact that adultery is not immoral in all cases, and that the dropping of litter is be the difference? I do not think that it is; one can conceive of a situation in which the dropping of litter ought to be excused – one might drop some objects to lighten their load while fleeing an attacker, for example. Furthermore there seems to be situations in which it is acceptable to kill another person, such as self-defence, which the law rightly makes allowances for. So the claim that adultery is not always immoral does not seem like a good reason to keep it unregulated; as any regulations could, as in the case of homicide, be designed so as to excuse adultery committed with good reason.
If it has nothing to do with both the public/private distinction and the non-universality of the immorality; what is it then that justifies our intuitions about the idea that adultery should be legal? I propose that the solution will be something like ‘the state needs to stay out of our sex lives’. What does this mean, though, and does it not beg the question? The statement ‘the state needs to stay out of our sex lives’ seems to me to be talking about our rights, specifically in this case the right to control our own sex lives in the way we want. Sex is an integral part of what it is to be a human being, and if this part of our bodily autonomy is controlled by others or the state, we lose a part of our humanity. There are still some complexities with this idea. We are not permitted complete autonomy with our own bodies; we cannot for instance use this autonomy to harm another person as in the case of homicide or assault. Even in the case of sex, we are only permitted to have sexual relations with consenting individuals.