Language is higher than a science; it is an art. By this I do not mean that it has no rules. In fact, I mean that we must master these rules, rather than letting ourselves be mastered by mere rules.
You have, for example, no doubt heard that it was said by them of old time, Never end a sentence with a preposition. But I tell you that such a rule is silly if followed absolutely.
I find helpful in this regard the Chicago Manual of Style, the 15th edition of which has the following on page 188:
The traditional caveat of yesteryear against ending sentences with prepositions is, for most writers, an unnecessary and pedantic restriction. As Winston Churchill famously said, "That is the type of arrant pedantry up with which I shall not put." A sentence that ends in a preposition may sound more natural than a sentence carefully constructed to avoid a final preposition...The "rule" prohibiting terminal prepositions was an ill-founded superstition.
Consider also this word from the inimitable work of Strunk and White, page 112:
The question of ear is vital. Only the writer whose ear is reliable is in a position to use bad grammar deliberately; this writer knows for sure when a colloquialism is better than formal phrasing and is able to sustain the work at a level of good taste. So cock your ear. Years ago, students were warned not to end a sentence with a preposition; time, of course, has softened that rigid decree. Not only is the preposition acceptable at the end, sometimes it is more effective in that spot than anywhere else. "A claw hammer, not an ax, was the tool he murdered her with." This is preferable to "A claw hammer, not an ax, was the tool with which he murdered her." Why? Because it sounds more violent, more like murder. A matter of ear.
Now, to be sure, let me say that I am not as loose with this rule as one might be tempted to conclude from my comments thus far. I do think it should be kept to a greater extent than it is generally today. The difference, again, is that between abandoning the rule, on the one hand, which I do not condone, and learning to rise above it and master it, on the other.
Also, let me add that some of these books, such as the Chicago Manual, or Strunk & White, to illustrate when it would be preferable to ignore this rule, give specific examples with which I personally might not agree. There is a degree of subjectivity involved here.
Now lest anyone conclude that what I advocate is the devolution of the language, it is worth pointing out that the rule of not ending a sentence with a preposition does not come to us from the classic age of the English language, but was part of the well intentioned and mostly brilliant enterprise of teaching that language later. The King James Version of the Bible does not know this rule. It violates it left and right. Take, for example, this sentence from the fourth chapter of the Book of Judith:
Thus every man and women, and the little children, and the inhabitants of Jerusalem, fell before the temple, and cast ashes upon their heads, and spread out their sackcloth before the face of the Lord: also they put sackcloth about the altar, and cried to the God of Israel all with one consent earnestly, that he would not give their children for a prey, and their wives for a spoil, and the cities of their inheritance to destruction, and the sanctuary to profanation and reproach, and for the nations to rejoice at.
Or this from Genesis, chapter 16:
And they that went in, went in male and female of all flesh, as God had commanded him: and the LORD shut him in.
Or this from John 4:
But he said unto them, I have meat to eat that ye know not of.
Nor does Shakespeare keep this rule, as we see, for example, when Queen Gertrude says in Hamlet:
Good Hamlet, cast thy nighted color off.
Or, indeed, later, when Hamlet economically says:
Of course, the list of examples could be multiplied. But you get the point. Finally, I am reminded of something Christopher Hitchens wrote in an essay against the decision of the Oakland School Board to treat "Ebonics" as an official "genetically based" dialect. In the midst of a broader argument, in which he explains that those born in the British Isles tend to have very distinct local dialects, he pokes fun at the wooden nature to which the language can succumb when such rules are kept too religiously:
Margaret Thatcher had to take several courses in elocution to rid herself of bumpkin and awkward tones and to become the queenly figure that I left England to get away from. (To get away from whom, I mean to say, I left England.) (Unacknowledged Legislation, 232, in the article "Hooked on Ebonics")