This article argues that Thomas Aquinas is to be interpreted as holding that the beatific vision of the saints is causally dependent on the glorified humanity of Christ. It opposes the view that, for Aquinas, Christ’s humanity has causal significance only for those who are being brought to the beatific vision by grace, and not for those who have attained this vision, such that there is a Christological deficit in Aquinas’s eschatology. The argument proceeds somewhat in the manner of an article of Aquinas’s Summa Theologiae. Having briefly outlined the recent debate, especially the contribution of Hans Boersma, two objections are put against my position. A sed contra is formulated on the basis of quotations from the Summa. The responsio is based on Aquinas’s extensive use of a philosophical ‘principle of the maximum’ and its particular application by Aquinas to grace. After replies to the objections, based on the method and structure of the Summa, I locate Aquinas’s position in the debate on Christ’s heavenly mediation between that of John Calvin and that of John Owen and Jonathan Edwards.