If the language of a will creates a future interest, when is there an implied condition that the one to whom the interest is given must survive the termination of prior interests? In general, this question is answered by applying the proposition that the law prefers to construe an interest as vested rather than contingent and as indefeasible rather than defeasible. Hence it would seem that, in order to imply a condition precedent of survival, there must be some language on which to base the implication. This, however, does not tell the entire story. There are numerous special rules applicable to particular language. And while most of these tend in the direction of the general doctrine just stated, a few, developed in particular jurisdictions, operate in the opposite direction.