A correspondent writes that he is worried about the potential ambiguity in such sentences as (the first one from Graham Greene):
(1) He did not dare to go up to where she slept, feeling that if he saw her face again he could not leave her.
where the feeling clause relates back to he, and
(2) He did not dare to go up to where she slept, dreaming of her new life in France.
where the dreaming clause refers back to she.
He wonders whether it is possible to interpret sentence (1) as referring back to she and sentence (2) as referring back to he. 'The participles are in the same place', he observes, so 'how can it be that they go with different subjects in each case'? How does one make it clear who is doing the action, in such cases?
Examples of this kind need to be discussed with reference to the distinction between finite and nonfinite. The above sentences contain participial clauses, which are literally 'not finite', i.e. they do not limit the action of the verb - by contrast with finite clauses, which do limit the action (typically by specifying the number, person, and tense involved). This means that there is always the possibility of grammatical ambiguity whenever a nonfinite clause is used. If I begin a sentence with Walking down the street... it is unclear whether the action is taking place now, or has taken place, or is yet to take place, and who or how many people is/are walking. Once the sentence continues with a finite verb, these matters are resolved: Walking down the street, I saw..., Walking down the street, she sees..., Walking down the street, they will see..., and so on. That is what finite verbs are for, to resolve ambiguity of person, time, and number.
So, faced with examples of the kind mentioned above, the only way to obtain the desired clarity is to go for a finite construction. In (2), for example, it would be more explicit to say: where she was dreaming of... - though the repeated wheres are not particularly elegant. And if it was he the writer had in mind, something like as he was dreaming... would make that clear.
However, such rewriting is hardly required in such cases, for our contextual awareness of the relationship between sleeping and dreaming makes the 'she' interpretation far more likely than the 'he'. Or, putting this the other way round, any writer who wrote sentence (2) wanting to convey the fact that it was the 'he' who was dreaming is doing something perverse - going against our normal contextual expectations. A restructuring of the sentence (such as He was dreaming of her new life in France, so he did not dare...) would be much clearer. Similarly, because we know that when people are asleep they are not 'feeling' in the sense of sentence (1), we are likely to rule out an interpretation in which the feeling refers to the sleeper.
My correspondent worries about how to resolve the question, but the answer is revealed in a telling phrase he uses: 'It is clear (if only from the context) that the participle 'feeling' describes the subject of the sentence'. That parenthensis is rather dismissive, and therein lies the root of the problem. Context is actually everything. Anyone who tries to analyse grammar as if it was somehow separate from the rest of the linguistic world is going to end up in trouble - seeing ambiguities everywhere! Grammar is never separate from meaning (semantics) and use (pragmatics), and all sentences have to be taken wholistically, with reference to these factors. In the vast majority of cases, potential grammatical ambiguities are avoided because our semantic and pragmatic knowledge tells us how to interpret them.
If you want to see this viewpoint developed in my own writing, take a look at Making Sense of Grammar (Longman, 2004), which applies the semantic/pragmatic perspective to English as a whole. I should perhaps add that prescriptive grammars and purist pedants are of no help whatsoever in such cases, as they condemn all so-called 'dangling' participles, regardless of context. So a sentence like Driving in from the airport, the flags were fluttering proudly - an illustrative sentence from John Humphrys' Lost for Words - elicits the comment 'What accomplished flags they must have been'. That is what happens when you let grammar govern your thinking to the exclusion of everything else. You lose all touch with reality!