> There is. A “bright and clear line” means a test is objective, not that it’s simple [1].

Except you were obviously not using the phrase in that sense? There is absolutely no contradiction between "objective" and "taking into account many details of the individual case". There is absolutely no problem with writing a law that objectively specifies that the punishment for "17 years and 364 day" is going to be only marginally worse than for "18 years", for example, which you used as an example for why a "bright and clear line" would be necessary, and that that would mean that you have to have to have a strict cut-off point between hard punishment and no punishment at all.

> There is. Just because something is not consistently enforced doesn’t mean it’s not clearly illegal. Cops may not fine you if they see you jaywalking, but you’re still unambiguously breaking the law if you cross the street outside of the crosswalk.

In other words: There isn't. If you are breaking the law, but there are pretty reliably no consequences, in which sense are you then breaking the law that would be relevant to this discussion?

> Most crimes (although not statutory rape) require intent to be shown [2].

In other words: For most crimes, there is less of a "bright and clear line", and things generally seem to be working well, or even better. So, how is that a justificaton for having more of a "bright and clear line"?

> No justice system is perfect; innocent people get convicted and guilty people go unpunished.

Well ... sure? I am not sure why you mention that?!

> A good law should allow people to unambiguously know when they would break it.

I am not sure I would agree with that. I mean, yes, ideally, people should be able to know in advance what would constitute breaking a given law and what would not, sure. But the problem I see is that this ideal goal is in conflict with other goals of a legal system, such as being just. And "bright and clear lines" in the sense in which you are using the phrase tend to have very nasty side effects in that regard, because they massively increase the probability that honest mistakes that harm noone are punished the same as premeditated harming of another human, but also that someone intentionally doing harm that just so happens to be on the legal side of the "bright and clear line" goes unpunished.

So, I would agree that laws should be as objective as possible in describing what is illegal. But at the same time, circumstances should always be considered so as to avoid injustice that results from overly simplistic rules being applied. That doesn't mean that judges should make arbitrary decisions, though, in that there is no problem with at least attempting to codify the details of how to justly judge individual cases rather than settling for the simplest rule possible. While you might never be able to codify all the possible things to consider, that does not mean that the only other option is to make a simplistic rule.

I’ve meant “bright and clear line” in the legal sense this whole time, yes. Try googling it: basically every result uses to it in the sense in which I’m using it, and none use it to mean “simple”.

> I’ve meant “bright and clear line” in the legal sense this whole time, yes.

Let me quote you:

> But here's the thing: the law can't take that into account. The law needs a bright and clear line, so you can know how not to break it. And so even though there's not really a difference between 17 years 364 days vs. 18 years, one can consent to sex with an adult while the other cannot.

So ... your argument was what exactly? That the law could not possibly spell out a more complicated rule than "below 18 is illegal", because ... it is impossible to do so in the English language? Or what?

That the law needs an objective way to determine whether or not one can consent to sex. It can’t be e.g. “has reached puberty” as another commenter suggested, because there’s a huge gray area where it would basically be up to the whims of the jury whether or not you were breaking the law. We use age because it’s an objectively measurable proxy for maturity, and it’s more or less correlated.

As it happens, statutory rape law is already more complicated than a cutoff at 18. There are often exemptions for people who are married, or close in age. But the line is still objective — a “bright and clear line”, so to speak.

So, you would agree then that it would be better to have a law that, say, made the transition from "illegal to have sex with" to "perfectly legal" gradual, as long as the rules are clearly spelled out? That is, a law that tries to avoid the situation where a very minor difference in objective reality corresponds to a massive difference in consequences?

If that is what you meant to say, you really didn't explain that well in your original comment, as you explicitly claimed that the law could not take details into account, rather than that it should specifically avoid subjective criteria. After all, it is perfectly possible to take into account the fact that not all people of the same age have the same maturity without resorting to subjective criteria--such as by making the transition from legal to illegal sufficiently smooth in terms of possible punishment that the punishment statistically scales with the probability of the sexual interaction being with an immature person: While that obviously does not perfectly match the consequences to the actual maturity of each individual, it would give a much better correspondence between punishment and the abusiveness of the relationship overall than a hard cut-off, while still being based on objective criteria.

Now, you are right that the law is actually usually more complicated than a single hard cut-off, but it seems that it's often still doing a poor job due to lack of nuance.