Difference between malum in se and malum prohibitum in law and how does it matter?

A brief summary:

For some reason, the law makes a distinction between laws as follows:

  1. Malum in se–meaning that the thing is bad in and of itself. Murder for example, is not bad because my state has enacted a law against it. It is immoral and wrong in and of itself in any decent society and is inherently wrong.

  2. Malum Prohibitum–meaning that the thing is bad because the law says it is bad. Wikipedia gives the example of how the U.S. mandates that a driver must drive on the right side of the road. There is nothing inherently indecent or immoral about driving on the left side of the road as is done in the UK, but it is a regulatory custom to promote safety on the roadways.

I have problems with this distinction, especially as my state has the concept of desuetude in which it comes into play: https://en.wikipedia.org/wiki/Desuetude

First, isn’t the purpose of a regulatory law to promote public safety? If I say, fuck it, I am now driving on the left side of the road, endangering children and the public, am I not now doing something inherently wrong?

Second, the distinction seems to smack of religion and natural law. Although I have no problem with this, I would assume many (especially posters here) would. But regardless of that, we still have the issue of says who? For example are adultery and bigamy malum in se? On one hand, they are not regulatory constructs: these prohibitions and the inherent wrong contained in them have been around since the Code of Hammurabi. But then again so was homosexual sodomy, so ancient proscriptions cannot be the test.

What makes something inherently wrong? Whose moral code do we go by? Jerry Falwell, Larry Flynt or some hypothetical reasonable person? Is this reasonable person allowed to consult the Bible in his deliberation?

Finally, if religion cannot be a factor, then we must acknowledge that all laws, including those against murder, are just human constructs and eliminate the distinction. If religion can be a factor, then the courts will have to decide that this particular religion or this particular sect has the right idea about what is intrinsically wrong, and that this other religion who is more tolerant of the idea has the wrong view of it. That cannot be done in U.S. courts.

I think the whole doctrine needs to be abolished as inherently subjective as the distinctions are ones that a judge can objectively apply.

Is this a legal or philosophical debate?

Fwiw, murder isn’t wrong in general. There are lots of time murder is acceptable.

Murder of a prisoner who committed serious crimes.

Murder in warfare.

Murder in self defense.

Murder of a lower consciousness (stepping on a bug).


Also many things are morally wrong but not illegal. Having an affair with a married person with children. Doing a layoff at work when the company is very profitable. Lobbying congress. Psychological abuse and non physical bullying.

For the most part, humans organize themselves into interdependent tribes. What counts as wrong is anything that threatens the survival of the tribe or those deemed useful to it.

But, those aren’t examples of murder.

  1. Both.

  2. None of the killings you describe are murder. They are killings. Except possibly euthanasia. If my father asks me to kill him because he has terminal cancer and is suffering terribly and I do so, that would be considered murder in my state. Is that inherently wrong or just a regulatory wrong?

  3. Your examples illustrate my point. Your moral code says that only having an affair with a married person who has children is wrong. Many people would say that was wrong regardless of whether the other person had children, while others would say that marriage is just a social construct and a contract and if the other person wants to breach it, that’s on them, not me.

  4. Your last point highlights the distinction. Of course what is “wrong” is what threatens the survival of the tribe. Murder would be one of those things. We cannot have that legal lest everyone be in a sniper’s nest worrying about someone killing him. We have a society because I cannot kill those people I want to kill, but likewise the law protects me from being killed by those who want to kill me.

But at the same time, society enacts laws for it’s “survival” by saying that everyone drives on the right side of the road, gets a number at the DMV instead of walking straight to a clerk, doesn’t smoke in a hospital, etc.

Why is murder intrinsically wrong, but those other harms are only harms because of the law?

Damn, I thought this was going to be a thread about Legally Blonde:stuck_out_tongue:
It’s an interesting question because to me, it seems like law is about who can “play the game” better, regardless of what society considers “right” and “wrong”. On one hand, it’s supposedly black and white, which is contrary to the grays and nuances of reality, yet on the other hand it can be spun, so it’s really *not *about right and wrong.

But does the law actually make a distinction? I’ve certainly heard of the idea of a conceptual difference between malum prohibitum and malum in se, but it’s not like our laws are actually divided into two categories of “malum prohibitum” crimes and “malum in se” crimes. Judges don’t actually say “Well, you’re guilty, but it’s only a malum prohibitum-type crime, so I’m going to let you off easy”. Rather, the legal penalties for murder are specified in our legal codes as being very severe–imprisonment for a long period, perhaps for life, or even the death penalty–whereas the penalty for parking your car on this side of the street (when the sign says that on Mondays, Wednesdays, and Fridays you must park on the other side of the street, so they can run the street-sweepers through) is specified to be a small-ish fine in the Traffic and Parking Code.

As for desuetude, it seems to me that’s a totally different thing. Regardless of whether mopery was considered an abominable and detestable act back in the 18th century when the law against it was first passed, or if it was outlawed merely because in our society we prefer dopery (but, hey, in some other countries they prefer mopery and ban dopery, and that’s also totally cool), the question with desuetude seems to be, are we actually enforcing the law or not? It may be tricky to specify when and how desuetude actually comes into play, but if Bob is the first person to be prosecuted for mopery in a century AND Bob can truthfully point out that lots and lots of people these days routinely mope–in public even!–and none of them has been arrested, just poor old Bob, then Bob has at least some kind of moral claim of unfairness.

This is just it. Under the desuetude doctrine, if mopery is malum in se, then Bob has no remedy, even if the law has not been enforced for years.

Why not? It’s the intentional killing of another sentient life form.

Where do you get that peculiar definition? Just looking at some dictionaries:

Mirriam-Webster: the crime of unlawfully killing a person especially with malice aforethought

Oxford Dictionaries: The unlawful premeditated killing of one human being by another.

Cambridge Dictionary: the crime of intentionally killing a person

Macmillan Dictionary: the crime of killing someone deliberately

OP"s problem lies in the assumption that malum in se is somehow fixed and universal. It makes no practical difference in the creation and application of law, save to the extent that public opinion might be sufficiently inflamed about something to be demanding that Something Must Be Done and There Ought To Be A Law. It’s just a shorthand for “whatever is generally considered at any given point in time to be egregiously wrong and beyond the pale”. It will inevitably change over time.