Thoughts on the Asinus Controversy

J. Neil Daniels

The asinus controversy, a term derived from the Latin word asinus meaning "donkey," refers to a speculative theological debate that emerged within late medieval nominalism, particularly among the followers of William of Ockham and his intellectual successors. The controversy centers on the question: Could the Son of God have become incarnate as a donkey (or in some other non-human form) rather than as a man, and still accomplished the redemption of humanity?

Background: Nominalism and Divine Omnipotence

Within late scholastic theology, particularly in nominalist circles, theologians were deeply interested in the scope of God's absolute power (potentia absoluta) versus His ordained power (potentia ordinata). According to this distinction:

• Potentia absoluta refers to what God can do in principle, unrestricted by any particular decree or order.
• Potentia ordinata refers to what God has willed to do within the actual economy of salvation.

This conceptual framework opened the door to speculative questions about hypothetical divine actions, namely, what God could have done, even if He did not actually do so.

The Donkey Christ Hypothesis

The asinus question was a deliberately provocative illustration of these speculative boundaries. Some nominalists asked whether the Second Person of the Trinity could have assumed the nature of a donkey (or any rational or even irrational creature) instead of assuming human nature, and still brought about the redemption of humanity.

This thought experiment was not meant to be taken literally in its pastoral implications, but rather as a way of highlighting the contingency of the Incarnation within nominalist theology. If God's actions are entirely based on divine will and not constrained by necessity, then hypothetically, He could have chosen any creaturely form to unite with.

Heiko Oberman's Analysis

In The Harvest of Medieval Theology: Gabriel Biel and Late Medieval Nominalism, Dutch theologian and historian Heiko Oberman (1930–2001) discusses this controversy in the context of Gabriel Biel and other late medieval theologians, especially in relation to William of Ockham’s theological method. Oberman highlights how nominalist thinkers explored the boundaries of orthodoxy by asking such hypotheticals: "Could the redemptive mission of the Logos have been fulfilled by assuming a donkey's nature?" Oberman notes that this speculation reveals how, for nominalists, the Incarnation was not metaphysically necessary. God could have chosen another means of redemption, and even another nature to assume.

Thus, Oberman argues, this line of thinking represents a shift away from the realist metaphysical theology of earlier scholastics (like Aquinas), for whom the assumption of human nature was fitting and in some sense necessary, given the logic of salvation history.

Theological Critique and Consequences

While late nominalist theologians employed the asinus hypothesis to underscore the boundless freedom of the divine will (potentia absoluta), many critics, especially among the early Reformers and post-Tridentine Catholic theologians, condemned such speculation as not only theologically unsound but also impious. They regarded it as a grotesque abstraction that violated the essential logic of the Incarnation and redemption. By entertaining the possibility of a non-human Incarnation, such as the assumption of asinine nature, nominalist theologians were seen as undermining the intrinsic and necessary connection between the true humanity of Christ and His redemptive work.

From the standpoint of classical orthodoxy, rooted in patristic, medieval, and confessional consensus, redemption required that the Redeemer be consubstantial with those He came to save. As Hebrews 2:14 affirms, “Since the children share in flesh and blood, He Himself likewise also partook of the same” (LSB). Christ had to assume human nature, not merely in outward appearance but in the fullness of human substance—body and rational soul—so that He could serve as the second Adam (Rom 5:12–21), bearing the penalty of human sin and restoring what was lost in the Fall. Only a true man could represent mankind as a federal head and perfect mediator (1 Tim 2:5).

Furthermore, the doctrine of the hypostatic union, as defined at the Council of Chalcedon (451), requires that the divine Logos united Himself to a rational, spiritual human nature. A donkey, being a non-rational animal lacking the imago Dei, would constitute an ontologically disqualified subject for such a union. To propose the possibility of a deus asinus (a "donkey-God") not only degrades the dignity of the Incarnation but also trivializes the very essence of divine self-revelation. It suggests a conception of God's will divorced from His wisdom and goodness, implying that the mode of redemption was arbitrary rather than intrinsically fitting (conveniens), as Thomas Aquinas and other classical theologians emphasized.

In this light, the asinus controversy stands as a paradigmatic instance of the speculative excesses into which late scholastic theology could fall when unmoored from scriptural and dogmatic boundaries. It highlights the dangers of an overly voluntaristic conception of God, wherein divine freedom is construed in abstraction from divine nature and purpose. Moreover, it illustrates the broader methodological tensions between realism, which affirmed the intelligibility and appropriateness of God’s actions within a created order, and nominalism, which tended to prioritize divine will above fittingness, reason, and theological coherence.

Thus, this debate is not merely an intellectual curiosity, but a revealing symptom of deeper theological shifts that were already destabilizing Western Christendom on the eve of the Reformation.

Further Reading

Heiko A. Oberman, The Harvest of Medieval Theology: Gabriel Biel and Late Medieval Nominalism (Cambridge, MA: Harvard University, 1963), esp. pp. 250, 255–258.

Marilyn McCord Adams, Some Later Medieval Theories of the Eucharist: Thomas Aquinas, Gilles of Rome, Duns Scotus, and William Ockham (Oxford: Oxford University, 2010), ch. 8.

Richard Cross, Duns Scotus on God (Ashgate, 2005), esp. ch. 7–8.