I'm thinking of an example where a law allows for certain things but not others. However, it's not that these things are prohibited, just that there is no law that allows them. In particular, at least a while ago, one could not obtain a patent in Canada for a computer algorithm. Patent law simply did not list "computer algorithms" as things that could obtain a patent. Therefore, it is not "illegal" to get a patent on an algorithm, it's just "impossible".

Is there a term for "not specifically allowed by law and therefore impossible, but not illegal per se"?

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    "Not recognised by law"? Dec 2, 2019 at 16:16
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    'Cases / devices / concepts not covered by existing laws'. Dec 2, 2019 at 16:34
  • It was eventually ruled that algorithms aren't covered by any of the terms included in the law, I suppose. Therefore it was forbidden by the law, although the court after having to spend hours upon hours to form an opinion will afterwards claim that they always knew and that it was always the case.
    – vectory
    Dec 2, 2019 at 18:31
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    I was told that ‘unlawful’ covered this (i.e. meaning something not specifically allowed by law, as opposed to ‘illegal’ meaning something specifically disallowed by law) — but Oxford indicates something slightly different.
    – gidds
    Dec 3, 2019 at 1:33
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    "There is no provision in Canadian law for patenting a computer algorithm."
    – TrevorD
    Dec 3, 2019 at 18:49

5 Answers 5


When the law for a situation is not established, it is a lacuna or gap. Gabriel Hallevy in A Modern Treatise on the Principle of Legality in Criminal Law (2010) gives a summary of how an absence of law can be perceived. The two interchangeable terms are gap and lacuna:

[It can be regarded as a negative opinion of the law, or] it can be regarded as a legal gap (lacuna) [...] where the law neither accepted nor rejected a legal settlement. In such cases, the judicial instance can resort to complementary sources of the law in order to fill the lacuna. The second way can be relevant to most spheres of the law [including patents], but not to criminal law, where lacuna juris is interpreted as a negative opinion of the law and not as a legal gap that can be filled by the court.

This terminology is used in an abstract in a recent issue of International Review of Business Ethics (Dec. 2018) to describe the absence of law surrounding networked objects:

Neatly nestled in a lacuna juris and surrounded by a lack of clinical evidence, networked toys raise complex ethical issues concerning human development. This article lays bare the regulatory nexus for networked toys and invites ethical thinking to fill the gap to ensure sufficient protection for all human developmental stages.

  • Learned a new word today. +1. I thought it was something to do with lagoons.
    – Nigel J
    Dec 2, 2019 at 17:33
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    @NigelJ Etymologically, I'm pretty sure they're related. They both come from the Latin word for a hole, and a lagoon is basically a really big hole full of water.
    – Hearth
    Dec 3, 2019 at 2:34
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    It's all about context. In human anatomy, lacunae (singular lacuna) are small holes in bone tissue containing osteocytes Dec 3, 2019 at 16:14
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    @MarcusHendriksen And in literary studies, lacunae are gaps in manuscripts left by mischievous authors or hungry worms. Dec 3, 2019 at 16:21
  • @Hearth Interestingly, the English words lagoon and lacuna can both be translated to the Spanish word laguna.
    – NMI
    Dec 3, 2019 at 19:49

It's two words, but the phrase "legally impossible" seems to be used that way.

For example, in Sneider, Allison L., Suffragists in an Imperial Age: U.S. Expansion and the Woman Question, 1870-1929, United Kingdom, Oxford University Press, 2008 (emphasis added):

[The Fourteenth Amendment] overturned nearly a century of state and federal law that had made it legally impossible for black men and women to become citizens in most states.

It was not illegal, in the sense that a person doing it could be punished by law; it was legally impossible, in the sense that the law provided no mechanism by which it could be done.

However, I admit that the phrase "legally impossible" is also used in other ways.

As one example, there was once a proposed "Constitutional Amendment Making War Legally Impossible," which actually stated that "War for any purpose shall be illegal." It would not have made war legally impossible in the above sense.

I've also found a few usages of the phrase "legally impossible" that seem to mean that a course of action would be impractical as a result of the laws in effect, rather than actually being impossible.

Finally, there is one very specific use of the phrase "legally impossible," which is the defense of legal impossibility. Suppose that somebody steals my wallet, but then sets my wallet down on a table in a public place. I reach out to take my wallet back, but the thief grabs the wallet again before I am able to do so. I am then accused of the crime of attempting to steal the wallet. In this case, it is said that it was legally impossible for me to steal the wallet, since it was my wallet—even if I had succeeded in taking the wallet, doing so would not have been theft. Since it was legally impossible for me to steal the wallet, I am not guilty of attempting to steal it.


While you may have problems with implications, I think "Extralegal" (outside the law) is the closest single word. Though, implication is going to be an issue no matter what you pick.

Unprecedented, or unlegislated might work better in your example. Or rephrase the sentence to specify that "computer algorithms" are unpatentable in Canada.


When I offer legal advice without beeing a lawyer in Germany I have to obey a few rules which limits my freedom to do this. For example, I may not earn money with it and need to be in good contact with a laywer who can help me when I am stuck.

Another of these rules is that when I want to offer encashement, this requries to get a "registration" as an encachement company (or person).

In order to do so, I have to take a 10 minute examination at the state high court - and then I am registered as "registered person".

Now you could think that it should be even easier to get into the registration list when you do not want to offer services which are only allowed with registration.

But this is not the case, you can only register something where registration is your duty. It is not forbidden, but impossible, and it is like that because of a law which indirectly excludes that.

I think you underestimate how often that situation is the case? :)

  • I think perhaps you mean encashment, rather than encashement or encachement.
    – NMI
    Dec 3, 2019 at 19:55

There is the concept that law only encodes the status quo, and directs course of action to maintain it. If something is not specifically forbidden but found deplorable, then the judgement will be subsumed under the basic blanket statements of the constitution--often without such big words but rather common sense.

In this case, it is specifically forbidden to go and take other peoples money for inventing an algorithm that you had invented before. That's common sense as encoded in the legal code, for each and every method that could optain the money, and these also count for the patent office, who have been however excempt in limited cases.

The law rarely speaks of forbidding; cp pro-hibition, OE forehaeldan, pro of the same root as forbid or equivalently Ger verbieten (with ver- in many cases nevertheless not always carrying a negative connotation, ca "off, away", or rather "before", cp ante, anti for analogy).

It rather speaks of rights, and modern philosophy assumes that everybody has basic human rights before the law, not to say independent of the law.

Corolarily: Of course it's not forbidden to accept reimbursement, donations, etc, but it can't be forced, not through the patent office.

Cp further "statutory interpretation" (with a degree of three links distance to de.wiki/exegesis, and one to Auslegung, viz teleologic exegesis), surely understood as statute.

I compare various words around standing, good standing, Ger anständig "good standing", verständig, understanding (Ger unterstellen seems to come through a sense "standing under shelter, be protected by believe, believe, allege, discredit, defame; cp support, Ger unterstützen); staendige Rechtssprechung "precedented sentencing" (ca steady, upright or continuous), and especially, which would answer your question: legalese statthaft "admissable, according to formal requirements; ? respectable" (as correlated to legalese zulässig "permissable, allowable; tolerable", begründet "justified, acceptable; ? well grounded"; cp statt finden "to take place"), Middle High German statehaft "able, equipped, esteemed, fortunate", Old High German unstatahaft (8th century; cp e.g. undead); Pfeiffer/DWDS also compared gestatten "allow", status quo. Also cp Gestalt "forma", Gestell "matrix, frame, support, rig".

That said, statutory is lexicalized chiefly as if from constitution. Through Latin we find related destitute ("lacking in something, forsaken", i.e. still having the death penalty), institute, etc, but I see no term other than unconstitutional that would fit your request in the modern context. Given the above allusion to pro (opposite of contra if I say so myself), as well as to "*public opinion" (i.e common sense) I'm inclined to suggest prostitute "to set up in public", but that's obviously nonsense; another contrast to con is sin "without" (Spanish as in "caffe sin lecho") and sinfull fits the underlying sense of law in many ways, however unknown the etymology.

irregular also comes to mind. But the exact terminus technicus for what you are looking at I don't know.

A correlate to de legis (by law) is de facto (for a fact). Like, many languages or only de facto official lamguage of a country. It is after all impossible to create an official law in an official language to designate the official language unless it already were the official language.

That said, there's probably a legal latin phrase meaning exactly what your example suggests. In textual canon there is:

Expressio unius est exclusio alterius ("the express mention of one thing excludes all others"), or "Expression of one"

  • "In this case, it is specifically forbidden to go and take other peoples money for inventing an algorithm that you had invented before." What does that mean? How do you invent something you have already invented? And surely there is no prohibition against someone paying you for inventing (or even reinventing) an algorithm.
    – David K
    Dec 4, 2019 at 12:50
  • @DavidK a) it is generally not allowed to take other peoples money--without permission; but as far as I know this rests on the privilige of ownership in the first place: it is specifically allowed to own money; consequently it is specifically forbidden to steal, black-mail, betray, etc. b) Algorithms are frequently rediscovered--perhaps that's a better word, but the difference is well difficult, and in some cases the difference is arbitrary, a matter of degree, not kind, or ... c) sure, I said so, but there are fair trade laws, and bad faith contracts; opposite of bona fides.
    – vectory
    Dec 4, 2019 at 17:26
  • I was going to ask what you have against software developers, or why you think reinvention of other kinds of patented devices or processes doesn't occur, but perhaps you are against patents altogether. Anyway, "unconstitutional" seems very far out of the scope of the question. (Something that is unconstitutional is, in fact, prohibited.) The "expression of one" at least is relevant to the given example.
    – David K
    Dec 5, 2019 at 4:30

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