Kathy Jolowicz fowarded this item from a words forum she frequents:
Suppose person #1 says that he's soon going to Athens and will visit the Acropolis. Person #2 replies: "That's great! But you want to go early in the day before the heat builds ... and before the tourists overrun the place."
Easier question: Is person's #2's line supposed to be "You want to ..." or "You'll want to ..."? (Or does it work either way?)
Harder question: What kind of a statement is #2's statement anyway? It's not a prediction (I guess). It just doesn't seem to fit into the normal pattern of past, present, and future for verbs. (As in "You went early," "You're going early" and "You will go early", where a person's going early is some event that's located in the past, the present, or the future.)
It may confuse things that the example uses "you want" in the old sense that refers to requirements rather than desires. The same questions come up if we phrase the same advice in another way, e.g. "It's better to go early in the day" vs. "It'll be better to go early in the day".
And the answer to the first question, it seems to me, is that it depends on what you mean. The "present-tense" versions are generic, i.e. timeless, while the versions with will make a somewhat more time-specific statement. There's not much difference in this case, since the generic statement is implicitly constrained to relevant times, and it's obvious in context that the relevant time is the period of person #1's visit to Greece. But my impression is that the generic versions of such advice are a bit politer, due to being vaguer.
As for the second question, I don't think there's much of a mystery. "Present tense" morphology is routinely used in English, as in many other languages, for generic statements, which are timeless or at least true at all contextually relevant times. And generic statements are often used to be give advice or to make advice-like predictions.
Posted by Mark Liberman at August 14, 2007 08:34 AM