Negation of probabilistic constructions

I came across the following sentence in an old Language Log post

"A recent New York Times article described the Japanese profession of hostessing, which involves entertaining men at establishments where customers pay a lot to flirt and drink with young women (services that do not, as a rule, involve prostitution)."

The question being asked there is whether "as a rule" here means that there is a rule that such services can not involve prostitution or rather that ther is no rule that says it must involve prostitution.

Mark Lieberman preforms a fairly extensive dive in how "as a rule" is used currently and how it used to be used and comes to the conclusion that "as a rule" doesn't imply there exists any rules, regulation or mandates. Instead just saying how things "generally are, not how they should be or must be."

This makes sense to me in that I also see "as a rule" meaning usually or in most cases. But to me that doesn't really answer the question, which seems to be more about how one should read the negation.

Parsing the sentence best I know how, I would have a slight tendency to favor the reading, that the provision of the services does not imply that prostitution is involved, although it could be. As opposed to parsing it as though provision of the services in most cases does not involve prostitution.

For the reading where in most cases prostitution is not involved I would expect a word order of "(services that, as a rule, do not include prostitution)."

I'm not really sure if this reading is correct in general and if it's really determined in how tight the negation is bound to the action.

Can anyone explain please?

Solution 1:

Yes, there is indeed a syntactical ambiguity here, in that as a rule could be understood (a) a part of what is being negated, or (b) as applying to the negation.

To see that this does make a difference, let's look at a similar example that exhibits the same syntax. Suppose that somebody said:

The services do not, in 80% of the cases, involve prostitution.

That could be taken to mean:

(a) It is not true that that the services involve prostitution is (as many as) 80% of the cases.

but it could also be taken to mean

(b) In (at least) 80% of the cases, the services do not involve prostitution.

On the first reading, the sentence says that only the percentage of the cases involving prostitution is somewhere between 0% and just below 80%; on the second it says that the percentage is less than 20%. Thus if it turned out that, say, 40% or 60% of the cases involve prostitution, (a) would be true, but (b) would be false.

Upon seeing such a sentence, I would probably be inclined to favour the first reading, principally on the ground that, if one intended (b), one could have easily avoided the ambiguity by saying 'In 80% of the cases, the services do not involve prostitution'. But (outside any disambiguating context) I couldn't completely rule out the possibility that (b) was intended.

Of course, the meaning of as a rule is not nearly as precise as that of in 80% of the cases, but the claim that the 'services . . . do not, as a rule, involve prostitution' gives rise to the same syntactical ambiguity. Taken on its own, it leaves it unclear whether the percentage of the cases involving prostitution is low (analogously to (b)), or just not very high, but possibly substantial (analogously to (a)).

Solution 2:

as a rule (phrase)

for the most part : GENERALLY m-w

Usually, but not always.
‘any architect knows that, as a rule, old buildings are more soundly built than new ones’ Lexico

If you say that something happens as a rule, you mean that it usually happens.
As a rule, however, such attacks have been aimed at causing damage rather than taking life. Collins

This represents about 14 per cent of the total population, about 18 percent of the total productive labor of the institution. As a rule, contractors get the choice labor of penal institutions. Prison reports do not show the quality of the labor let to the contractors, but no doubt the labor so let in Illinois penitentiaries is no exception to the rule.

The long term prisoner is undoubtedly more productive financially as a rule. ref.

Placement with negation:

It does not as a rule apply when existing buildings are altered to cater for disabled people, involving perhaps the provision of a ramp in place of steps... ref.

The living artist, the struggling artist, does not as a rule make money or benefit when the price of his work increases. ref.

The banks, as a rule, do not pay interest on deposits, do they? ref.

The man in debt, as a rule, does not care so much about seeing his savings account grow larger as he does to see the debt growing smaller. ref.

As for placement, either position works:

services that do not, as a rule, involve prostitution = services that do not usually involve prostitution

services that, as a rule, do not involve prostitution = services that usually do not involve prostitution

I have not yet come across an example where placement before or not makes a significant difference.

The Cambridge Dictionary has a table classifying adverbs and adverbial phrases with their positions.

EGEL classifies as a rule as a non-bounding frequency adjunct, in a subgroup that "contains a variety of frequency idioms:"

now and again, again and again, off and on, on and off, from time to time, as a rule, for the most part (p.715)