"x x x.
Failure to state a cause of action refers to the insufficiency of the pleading, and is a ground for dismissal under Rule 16 of the Rules of Court. On the other hand, lack of cause action refers to a situation where the evidence does not prove the cause of action alleged in the pleading. x x x If the allegations of the complaint do not aver the concurrence of the elements of cause of action, the complaint becomes vulnerable to a motion to dismiss on the ground of failure to state a cause of action. Evidently, it is not the lack or absence of a cause of action that is a ground for the dismissal of the complaint but the fact that the complaint states no cause of action. Failure to state a cause of action may be raised at the earliest stages of an action through a motion to dismiss, but lack of cause of action may be raised at any time after the questions of fact have been resolved on the basis of the stipulations, admissions, or evidence presented.
x x x."
