by
Problem Sentences:
by omitted:
By means 'by means of' in sentences like the following:
He came by car.
He entered by the back door.
He passed the exam by studying diligently.
Although the restrictions on this use of bv are not altogether clear, one seems to have to do with definiteness, or the specificity--as opposed to abstractness or generality--of the relationship between the prepositional phrase and the verb. In most cases, there is a one-to-one relationship (of means) between the verb, which expresses what the event or action was, and the by phrase, which expresses how it happens (or happened, will happen, etc.). In other words, how the event occurs is explained by the by phrase--at least insofar as the context requires an explanation. This is not quite so in (4) and (9). In these sentences, the relationship between the predication in the main clause and the by phrase is more indirect than in the three examples given above. Compare the following sentence with (4):
People should come to know each other by correspondence.
This expresses a direct relationship between the proposition that people should come to know each other and how they should do so (the implication of the sentence being that correspondence should ease the way to face-to-face meetings, etc.). But in (4) the intended meaning is that one of the many things literature should do for people is help them get to know other people (e.g. fictional characters, subjects of biographies, etc.). Through is preferable here, because it expresses a less direct relationship than by. Similarly, in (9) growing older cannot be understood as the direct answer to the question "How does one's memory develop?", as in, for example, the following sentence:
One's memory develops by the growth and expansion of nerve cells in the brain.
Growing older is of course a concomitant process, but it is not the direct means by which memory develops, as the by phrase implies.
(7) presents a somewhat different case. There is a one-to-one relationship between had fun and by playing the guitar, but here the oddity is that the expression of means, however direct, is not appropriate. It would be unusual to respond to a statement like I had fun last night with the question How? There are contexts, of course, where How?--the question of means--is appropriate with a verb like have fun, e.g.:
How do you have fun in an igloo?
By playing it cool!
In this pun, by playing it cool ostensibly expresses the means by which an activity having fun) is accomplished. In (7), although there clearly is a relationship of means between the main clause and the bv phrase, the intention is not to express this relationship per se,, but rather a much looser one, which is harder to describe and categorize. Compare the following sentences:
He got a headache trying to figure out his tax return.
He stayed up all night waiting for her.
By in either of these sentences would imply purpose--that he wanted to get a headache and to stay up all night. Thus by phrases tend to express not only means but purposive means. We can see this in (7) as well, if the main clause is changed to something that clashes with the purposive implication of the bv phrase:
*I always got so bored by playing the guitar that I decided to quit.
The sentence sounds odd because it illogically implies that I played the guitar in order to get bored. Remove by and the sentence is perfectly acceptable, just as the two examples above, with the -ing participle clauses having a rather loose and variable semantic relationship with the main clause which Quirk et al. call "supplementive":
...what they describe is a "contingency" or "accompanying circumstance" to what is described in the main clause. "Contingency" may be interpreted, according to context, as a causal or temporal connection, or perhaps most commonly of all, a "circumstantial" one. In -ing clauses, dynamic verbs typically suggest a temporal link, and stative verbs a causal link... (1972:§11-50).
The loose or protean semantic relationship that a supplementive clause has with the main clause is reflected in the fact that usually more than one paraphrase is possible. This doesn't necessarily mean the sentence is ambiguous (though it might be); the -ing participle clause may simply have all or a combination of various meaninqs. The most likely paraphrases of the corrected version of the sentences mentioned above are:
I always had so much fun when/while I was playing/played the guitar.
He got a headache when he tried/while he was trying/after he tried/as a result of trying/because he tried to figure out his income tax return.
He stayed up all night because he was waiting/as a result of waiting for her.
With a passive verb, by introduces the agent or instrument of the action expressed by the main verb, e.g.:
He was hit by a muscle-bound thug (agent)
He was hit by a bullet (instrument)
As it stands, (3) must be understood to mean that the replacement (agent) chose Rocky, though the intended meaning was that someone unspecified chose Rocky as the replacement (i.e. for another boxer--reference to the film "Rocky").
In (8) and (6) the preposition is bound to a specific lexical item: listen to the radio, listen to something on the radio, enjoy something for (i.e. because of) certain qualities. In time in (4) is not the same as in time meaning 'punctually' (compare on time) but means 'eventually, after some time has elapsed'.