This account denies what some philosophers assume to be obvious, that “distinct and incommunicable intellectual acts and volitional acts are necessary conditions for being a person” (339). Williams rejects this as an ungrounded modern assumption. While it employs recent thinking about indexical terms and other matters, Williams considers this account to fit well with historical theologians such as Gregory of Nyssa, Henry of Ghent, and John Duns Scotus (345). That the persons share all mental acts does not imply that they share one mind or that there is one consciousness in the Trinity. Rather,...