What is correct syntax with 'entail'?
My instinct is that when it means "to have as an inescapable consequence", entail must be followed by a noun. In all the grammatical examples I have come across this is how it is used — without it being specifically remarked upon. For example:
- This responsibility entails hard work.
- The new job entails regular travel.
- Motherhood entails sacrifice.
But some people use it in sentences like
- When I blush it does not entail that I am embarrassed.
- My lisp does not entail that I cannot be a good singer.
- I am old, but that does not entail that I am also hard of hearing.
Is the usage "... entail that..." grammatically correct?
It's not "entail that" per se, but it is a grammatically correct construct.
"That I am a bad singer" is a kind of declarative content clause, also conveniently called a that-clause. These clauses can be used as direct objects for a number of verbs, and entail happens to be one of them. Blocking out the sentence structure as [Subject] [Verb] [Object], we have:
[My lisp] [does not entail] [that I am a bad singer]
In this structure, that can usually be omitted:
My lisp does not entail I am a bad singer.
Personally I wouldn't (and this example looks odder than most), but I do tend to keep words others would elide out.
It is definitely correct to say "...entail that...", whether or not it is a "that which".
My lisp does not entail bad singing.
My lisp does not entail that I cannot be a good singer.
My lisp does not entail that which means I cannot be a good singer.
All are correct, although the third is unnecessarily tedious.
Since entail means to have as an inescapable consequence, you can replace entail with that definition in all of the above sentences.
My lisp does not have bad singing as an inescapable consequence.
My lisp does not have as an inescapable consequence that I cannot be a good singer.
My lisp does not have that which means I cannot be a good singer as an inescapable consequence.
Disclaimer: I would not recommend any of the last three atrocities for actual use - they are meant for illustrative purposes only.