Hypersmurf said:
I agree that identifying the spell and countering it are distinct... but you stopped highlighting too soon.
Make a Spellcraft check. "If the check succeeds, you correctly identify the opponent’s spell and can attempt to counter it. If the check fails, you can’t do either of these things."
If the check fails, not only can you not identify the spell; you explicitly cannot do either of the two things, identify or counter.
Unless you're using Dispel Magic.
The way it's phrased it seems pretty clear to me that "attempting to counter [the spell]" only can't be accomplished because you haven't identified it, and thus don't know what spell(s) could be used to counter it. (It doesn't mention random selection of a counterspell, but I don't see any reason that wouldn't work except for the difficulty of randomly guessing which spell the caster has chosen.)
What's the difference between identifying a casting of Fireball by viewing the V/S components of the spell, and knowing that the spell being cast is Fireball (for example, if the casting mage had told you immediately beforehand that he was casting Fireball, or you used some sort of divination to discern the caster's next action--mind reading, for example)?
I think I'll submit a question to the Sage. I don't think you can definitively say, based on the pure text, whether
identifying the spell via Spellcraft is necessary, or whether the requirement is merely to
know what spell is being cast, but the former seems pretty illogical. (Not that the rules are always, or even often, logical

but this seems like a case where there's no reason not to be.)