MichaelWhat is your question exactly?
Do you want to give a critique of Murphy's text or figure out the usage of "some" and "any", regardles of Murphy's opinion?
Не нравится Вам Мёрфи, возьмите другой учебник.
Determiners
Some and Any We use the determiners some and any to speak about indefinite quantities or numbers, when the exact quantity or number that we are thinking of is not important.
Нужно какое-то правило. Очевидно, мы им не располагаем.
In the most basic terms, we can say that we use some for affirmative statements, and any for questions and negative statements: I need some new clothes.
We haven't got any sugar.
Do you have any pins?
It is possible, however, to use some in questions and any in affirmative statements in certain circumstances.
When we are make an offer, or a request, and we want to encourage the person we are speaking to to say "Yes", we use some in our question:
Would you mind getting some bread while you're at the shops?
Shall I bring some drinks to the party?
We use any in affirmative statements if it comes after a word whose meaning is negative or limiting:
He never does any good deeds.
She rarely has any food to offer us.
They neglected to offer any advice.
Just do it without any fuss or bother!
In conditional sentences, we can often use some and any with no difference in meaning:
If they need some/any more supplies, they should just tell us.
The same rules that apply for some and any also apply for somebody/anybody, someone/anyone, somewhere/anywhere, something/anything:
He never does anything bad.
I need somewhere to sleep.
Do you know anyone who could help us?
More information about some and any:http://www.fortunecity.com/bally/durrus/153/gramch20.html#5