wait-and-see principle.A modification to the rule against perpetuities, under which a court may determine the validity of a contingent future interest based on whether it actually vests within the perpetuities period, rather than on whether it possibly could have vested outside the period. —  Also termed second-look doctrine. [Cases: Per-petuities  4. C.J.S. Perpetuities §§ 2, 12.]
[Blacks Law 8th]