Pasnau's top-10 list of grammatical errors for the advanced student.

10. Don't confuse i.e. and e.g.

e.g. (exempli gratia) = for example, for instance

i.e. (id est) = that is, in other words

9. Know when to use whom and who.

Although whom usually sounds pretentious in spoken English, it should still be used in written English. Use who when it serves as the subject of a clause. Use whom otherwise.

RIGHT: To whom do you refer?

RIGHT: I refer to the man who gave you that book.

RIGHT: I refer to the man whom you see over there. [In this sentence, whom is the direct object of you see.]

8. Split infinitives.

WRONG: I try to carefully choose my words.

RIGHT: I try to choose my words carefully.

I confess that it’s not entirely clear to me why split infinitives are objectionable. Perhaps the best reason for avoiding them is that this tells the discerning reader that this is a careful writer at work. Often, however, it will sound much more natural to split the infinitive: e.g.,

The goal is to better preserve books in the library.

Here the adverb cannot be moved elsewhere without creating ambiguity or awkwardness. In such cases, either rewrite the sentence entirely or shrug your shoulders and live with the split infinitive.

Note: This rule does not apply to compound verbs of all sorts, but only to the infinitive: to be, to run, to say, to hold, etc.

7. Beware of the singular and plural forms of certain nouns with Greek origins:

The criterion is clear.

The criteria are clear.

What is the phenomenon?

What are the phenomena?

6. Avoid beginning sentences with the conjunction however, because it is liable to be taken as an adverb.

WRONG: However, these are not good reasons.

RIGHT: These are not, however, good reasons.

5. Use while only to express temporal concurrence, not to make a contrast between states of affairs. To express contrast, whereas and although are less ambiguous and hence preferable.

RIGHT: While I was talking, she kept right on working.

WRONG: While I preferred this, she did that.

RIGHT: Although I preferred this, she did that.

4. Use hyphens in compound adjectives only when the words are to be read together as, in effect, a single word. A good test is to consider whether the main adjective could stand on its own. Hence,

RIGHT: thirteenth-century theology

RIGHT: a most impressive volume

RIGHT: a worked-out theory of consciousness

RIGHT: a well developed answer

3. The subject of a gerund must be a possessive:

RIGHT: Dave's running to the store saved the day.

RIGHT: We were grateful for his running to the store.

WRONG: We were grateful for Dave running to the store.

2. That and which

Although completely lost in casual English, the distinction between that and which is extremely useful when writing precisely, and so extremely useful in philosophy. The rule is to use that with a restrictive clause and to use which with a nonrestrictive clause, set off by commas:

RIGHT: She accepted the first answer that seemed true.

RIGHT: She accepted the first answer, which seemed true.

[Notice that these sentences express entirely different propositions.]

1. Careful placement of adverbs

Casual English is extremely casual about the placement of adverbs. Careful prose takes care to locate adverbs in such a way as to indicate what they modify. Again, this is particularly important in writing philosophy.

WRONG: You should only consider this in your actions…

RIGHT: You should consider only this in your actions…

WRONG: This is not true for you, but for me.

RIGHT: This is true not for you, but for me.