# How would one interpret: “must not exceed X and Y” vs “must not exceed X and not exceed Y” [closed]

EDIT/NOTE: This phrase is from a legal document, so rules of plain language / literal interpretation are assumed to apply, so please refrain from assuming what you believe was intended by the writer. THIS IS NOT A LEGAL QUESTION, but one about proper grammatical logic. It would be highly appreciated if you referenced English grammar rules to support your point.

I've been debating with someone over the correct grammatical interpretation of the following sentence:

Structure must not exceed 12 feet by 12 feet base and 12 feet in height.

I am fairly convinced this means the structure must exceed both base and height dimensions in order to fail to meet the requirement. However they argue if the structure exceeds either base or height dimensions, then it will fail to meet the requirement.

• Here are the two ways this could be logically interpreted, both returning opposite results:

H = 10, B = 20

not (H > 12 and B > 12) ------> True

not H > 12 and not B > 12 ------> False

I believe my interpretation is correct since there is only a single "not exceed", as well as no commas in the sentence. Whereas if the sentence said "not exceed ... and not exceed..", then that would follow the second logic:

Structure must not exceed (12 feet by 12 feet base and 12 feet in height) ------> True

Structure must (not exceed 12 feet by 12 feet base) and (not exceed 12 feet in height) ------> False

Furthermore, if the sentence used an "or" instead of "and", then that would mean that exceeding either constraint would result in failure to meet the requirement:

Structure must not exceed 12 feet by 12 feet base or 12 feet in height.

### Grammatically speaking, I believe the "and" is a coordinating conjunction forming a compound object, upon which the "not exceed" is acting singularly to both objects. Is this accurate?

• I don't think it needs much grammaticaI analysis: fairly sure that the requirement limits the structure's size in all dimensions, not selectively, which makes the statement unambiguous. To stretch the point, a structure which is 1 mile high won't be allowed just because its base is 11 feet by 11 feet. – Weather Vane Feb 14 '19 at 20:30
• Conjunction Reduction always removes information. (As a rule it's optional, except in some fixed phrases, and it often allows several possibilities in a given sentence.) When information is removed, ambiguity is more likely. In an ambiguous sentence, the interpretation by the addressee cannot be controlled. – John Lawler Feb 14 '19 at 20:46

Welcome to ELU, and thank you for an interesting and carefully thought-out question. And you have a point. For example:-

You should not consume wine and pork.

This is troublingly ambiguous: it seems that as long as I refrain from one of them, I have fulfilled the requirement: especially if we are following the rules of formal logic, according to which A&B <--> not (A and not B) {A and B implies not (A and not B)}. Only the obvious context of Jewish and Islamic practice makes it obvious that both are forbidden. So we had better say instead:

You should refrain from wine and pork.

Now there is no possible doubt: you cannot have either. The grammar forbids it. But we have to remember that in the rules of propositional logic, 'A' and 'B' stand for propositions.

Structure must not exceed 12 feet by 12 feet base and structure must not exceed 12 feet in height. or rather: It must be the case that structure does not exceed 12 feet by 12 feet base and it must be the case that structure does not exceed 12 feet in height.

Both clauses must be true for the whole rather clumsy disambiguated sentence to be true. Negatives present a minefield of ambiguity. You have smartly prevented answerers from resorting to common sense to say that it is obvious, in the context of building permits that both height and footprint are subject to the scale limit.

You are also right to say that the conventional way round this logical ambiguity is to use the disjunction 'or' However, even this does not remove ambiguity, as 'not A or B' means 'not A implies B'. So we have to have 'neither A nor B'. In other words, to prevent any possibility of ambiguity we should have to say:

Structure must not exceed either 12 feet by 12 feet base or 12 feet in height.

I wish all writers paid the attention to univocality that you are paying. However, sadly attention to precision of meaning seems to be in decline. And grammar, as a system of classifying what people actually do must sooner or later follow usage, which is, after all the the key final word of ELU.

• Thank you for the reply. I'd also like to point out that the example I gave in my post was from a legal code, which inherently necessitates unambiguous wording, and it is typically the case for legal documents to use redundant wording for clarity. As well, in the mentioned document, there are no context clues that would clarify it, as there would be in the bible, like you mentioned. – John Feb 14 '19 at 22:47
• If it were really true that legal code were inherently and necessarily unambiguous then large numbers of lawyers would be out of work. When real life ambiguities occur in legal documentation the courts look at the whole context, not just a sentence in isolation. That is important in this case since the OP says that other parts of the document bear on the dimensions. – JeremyC Feb 14 '19 at 22:55
• @JeremyC I didn't say that legal code is never ambiguous, just that the expectation is for it to be unambiguous - or rather, the expectation is for it to be interpreted in plain language. In legal situations, courts are expected to interpret statutes in plain english with minimal assumption, and only resort to their own interpretation if that plain interpretation ends up being overly absurd or non-sensible. Also I am OP- the mention about other restrictions in the document was to point out that the plain-language interpretation was not "absurd", ie, wouldn't allow a 1000000x1000000x11 building – John Feb 14 '19 at 23:42
• @JeremyC Yes, if the legal writing has failed to be or been unable to be unambiguous, context has to be taken into account. But how it should be taken into account is often disputed as in the US right to bear arms. The aim, nevertheless, clarity. – Tuffy Feb 15 '19 at 1:11
• @John One thing we learn is that in legal documents avoid negatives if at all possible, and that where they are necessary, spell it all out in full, however tedious. – Tuffy Feb 15 '19 at 1:15

It is ambiguous, there is not a answer which will determine if the correct interpretation is

• must not exceed both X and Y
• must not exceed at least one of X or Y

It if comes from legal code, then the only source of truth is case law depending on your jurisdiction, or a legal judgement.

• It should be noted there is a difference between social ambiguity (what is reasonably expected), and grammatical/plain language ambiguity. The phrase has social ambiguity, but not plain language ambiguity. Interpreting it in plain language with no/minimal assumption leads to a single explicit interpretation. In legal situations, the standard is to interpret the plain language, and only if that plain language sounds absurd would the court resort to its own interpretation. – John Feb 14 '19 at 23:38
• It seems you are not asking an English language question but a legal question, and as I understand it the law and caselaw is ambiguous about the answer as well. If you really need an answer ask a lawyer or go to court. It also seems that you are not really asking a question but looking to confirm your position and the only answer you would accept was one that agreed with your interpretation. – colechristensen Feb 15 '19 at 1:42
• I have to disagree on both points. I asked a question and presented my evidence/research for my view, and then I asked people what the grammatically correct interpretation was based on English grammar rules. Most of the replies have not included any references to grammar rules, thus I've had to repeatedly stress that this is what the focus is. The only relevance the law/court has to the discussion was to point out that they just happen to be an entity which relies upon strict grammar interpretation, whereas social norms do not. This is not at all a legal question, but one of grammar. – John Feb 15 '19 at 2:05
• @mama The sentence IS ambiguous socially, but grammatically it has a single function. There is a single subject, a verb portion, and a compound object formed by virtue of the conjunction "and". However as mentioned, social context rarely follows strict grammatical rules, and is dependent on assumptions based on social context like you mentioned. – John Feb 15 '19 at 3:11
• @John It is you who doesn't understand the answer. There is no such thing as "plain language interpretation". There are "plain language interpretationS". And that is what I and everyone is telling you. But you imagine for some reason that that cannot be, even though that happens in absolutely all languages, from natural languages such as English, to formal languages. – mama Feb 15 '19 at 3:55