Many venerable norms in inheritance law were designed to prevent forgery. Most prominently, since 1837, the Wills Act has required testators to express their last wishes in a signed and witnessed writing. Likewise, the court-supervised probate process helped ensure that a donative instrument was...

The civil justice system has struggled to resolve disputes over end-of-life transfers. The two most common grounds for challenging the validity of a gift, will, or trust—mental incapacity and undue influence—are vague, hinge on the state of mind of a dead person, and allow factfinders to...