Ecce Homo: On the Divine Unity of Christ by Aaron Riches (review)

Aaron Riches begins this extraordinary book by quoting Pope Pius XII's Sempiternus Rex, in which the Pope emphasized that Christ's human nature must not be presented as though it existed on its own rather than in the Word. Riches notes that Pius XII's teaching on the fifteen-hundredth anniversary of the Council of Chalcedon squares with the Apostle Paul's affirmation of "one Lord Jesus Christ" (1 Cor 8:6; cf. the Niceno-Constantinopolitan Creed) and belongs to the Church's fundamental teaching that "the human Jesus … shares a unity and identity with God (in the person of the Son and Logos)" (3). On this basis, Riches sets forth the thesis of his book: "Therefore, the only tenable starting point for Christology lies in the absolute unitas of the human Jesus with the divine Son. This opposes any alternative starting point that would begin from a theoretical or ontological sepa-ratio of divinity and humanity in Christ in order to proceed discreetly 'from below'" (ibid.). Central to his argument is the point that no separation from God is needed or helpful in determining what Jesus's human nature is or does.

Riches gives two reasons in support of this argument. The first reason involves a paradox, given the incompatibility of the divine attributes (for example, that God cannot change and is eternal) with creaturely attributes. While differing infinitely from his divinity, Jesus's humanity cannot be truly known outside the union of his human nature with the divine nature in the Word. Riches remarks that, "if the reality of the human being 'Jesus' is ontologically constituted through union with the Logos, the human birth and real crucifixion of this human being is made possible only in the divine unity of the Logos" (5). There would literally be no human nature of Jesus if there were no union of that human nature with the divine nature in the Word, and so understanding Jesus's humanity cannot involve bracketing his divinity.

Second, and correspondingly, no separation from God is needed or helpful for analyzing Jesus's human nature because, in fact Jesus is verus homo et verus Deus, and so "the fullness and excellence of perfect humanity is constituted by the intimacy of its union with God" (6). Whereas it might seem that union with God makes Jesus less truly human, in fact, it makes Jesus more truly human. To know what is truly human cannot be attempted, therefore, by bracketing God. Rather, human nature becomes more what it distinctly is the more it is united with God. Riches states that "the irreducible difference of the human being in relation to God is perfected in direct (as opposed to inverse) relation to the perfection of the unio of his humanity with the divine Logos" (7). We might think that what is truly human is known and protected in Jesus by downplaying or bracketing what is truly divine. But, in fact, the opposite is the case, as befits the Creator God's ontological noncompetitiveness with creatures. When we emphasize Jesus's full divinity, we illumine his true humanity. Riches argues that the same point extends to knowing our own human nature, which is known rightly when we know it as united to the divine nature in the Word. As Riches puts it, "only the confession of the 'one Lord Jesus Christ' maximally preserves the integrity and difference of verus homo before verus Deus" (7). Indeed, Riches makes the point even more strongly, denying that we can begin in any way "from an abstract idea of what his humanity might be apart from that unio" (8). The suggestion is that, to know what true humanity is, we must look to Christ, and we cannot import a concept of true humanity from outside the hypostatic union.

Riches has in mind first and foremost the two main Christological heresies, Monophysitism and Nestorianism. Monophysitism appears to strongly affirm the unio, but it does...