Humani Generis

Background and Occasion

By the late 1940s, a new theological current had emerged in France and (to a lesser extent) Germany, which its critics called the nouvelle théologie. The figures associated with it — Henri de Lubac, Jean Daniélou, Yves Congar, Marie-Dominique Chenu, and others, mostly Jesuits and Dominicans — were learned, devout, and pastorally motivated. They sought a renewal of theology by a return to the patristic and early scholastic sources, a closer engagement with modern philosophy, and a more historical and existential mode of theological argument. They were genuinely concerned that the manualist tradition had become rigid, repetitive, and disconnected from the lived experience of the Christian faith.

But the new theology had also produced positions that touched the deposit of faith. Some of its proponents questioned the natural-supernatural distinction in its received Thomistic form, treating the natural desire for God as itself a supernatural orientation. Others gave dogmatic formulations a heavily historical character, treating them as expressions of a particular epoch’s understanding that might require radical reformulation in a later epoch. Still others were engaging with evolutionary biology in ways that touched the traditional doctrine of monogenism (the descent of all human beings from a single original pair) and of original sin.

Outside these specifically Catholic developments, the broader intellectual climate had also raised difficulties. Existentialism, in its various Heideggerian and Sartrian forms, posed questions about the nature of being and of human existence that did not fit easily into the categories of the manuals. Marxist materialism and its sympathisers within Catholic intellectual circles were reviving theological liberalism in new forms. Modernist tendencies that Pascendi had thought to lay to rest were re-emerging in altered language.

Pius XII judged that a magisterial response was now necessary — not to condemn the nouvelle théologie by name, nor to forbid all theological renewal, but to identify the errors that had begun to circulate and to set out the principles by which sound theological work must proceed. Humani Generis, promulgated on 12 August 1950, was that response.

Central Teaching

The encyclical does not have a single doctrinal centre. It is a survey of contemporary errors and a reaffirmation of corresponding doctrinal principles. Its structure follows the topics it treats: the relationship between faith and reason, the use of philosophy in theology, the nature of dogmatic formulation, the doctrine of creation, and the doctrine of man.

Reason’s Capacity for Truth

Pius XII opens with an affirmation of reason’s natural capacity to reach truth — including truth about God. He observes that this capacity has been weakened by sin and is in fact often impeded by passion, prejudice, and inherited error; consequently, divine revelation is morally necessary for the human race as a whole to attain even those religious and moral truths that are in principle accessible to reason. But the capacity itself remains: human reason can in principle know the existence of God, the spirituality of the soul, the foundations of natural law. This is the teaching of Dei Filius (1870), here reaffirmed against the various forms of immanentism and fideism that would deny it.

The Use of Philosophy in Theology

The encyclical addresses with particular care the proper use of philosophy in theology. Pius XII does not require that Catholic theologians use Thomism in some narrow, school-bound sense; the manualist tradition itself contained substantial variety. But he insists that any philosophy used in the service of theology must possess certain characteristics: realist epistemology (the capacity of the mind to know reality as it is), a stable doctrine of being (sufficient to support the analogical predication of being to God and creatures), and a sufficient grasp of the principles of metaphysics (causality, contingency, the transcendentals) to support the formulation of revealed doctrines.

The encyclical warns against several philosophical tendencies of the day. Phenomenology, in some of its forms, may suspend metaphysical commitments in a way that ultimately deprives theology of necessary tools. Existentialism may exalt the concrete and the historical at the expense of stable essential structures. Evolutionism, transferred from biology to philosophy, may dissolve the stability of being into mere process. Without naming any contemporary philosopher, the encyclical urges that Catholic theologians not embrace these tendencies uncritically.

Dogmatic Formulation

A particularly important section addresses the nature of dogmatic formulations. Some of the nouvelle théologie had been suggesting that the formulations of dogma are bound to the conceptual frameworks of the cultures and epochs that produced them — that, for example, the Tridentine doctrine of transubstantiation is intelligible only within Aristotelian categories and must be reformulated for a non-Aristotelian age.

Pius XII rejects this position. The dogmas of the Church are formulated in concepts whose use of philosophical terminology is not accidental to the truth being expressed. To change the formulations radically — to abandon the categories within which the dogmas have been defined — is to risk altering the substance of what is taught. Theological vocabulary can be developed, clarified, and supplemented; it cannot be jettisoned. The Catholic theologian writes within a living tradition, building on the formulations of his predecessors rather than starting over from scratch.

This teaching has had a complex history. Vatican II’s Dei Verbum and other documents would acknowledge a more historical dimension to dogmatic development than the strict reading of Humani Generis suggests, but the underlying principle — that dogmatic formulations express the truth they convey and cannot be radically reformulated without altering that truth — has been consistently maintained, most recently in Mysterium Ecclesiae (1973).

Evolution and the Human Person

The encyclical’s treatment of evolution is more permissive than is sometimes remembered. Pius XII teaches that the magisterium does not forbid Catholic researchers from investigating, by the methods of their respective sciences, the question of whether the human body has been formed by a process of evolution from previously existing living matter. The doctrine of evolution, considered as a scientific hypothesis about the origin of the human body, is not in itself incompatible with Catholic faith. What is required is that the soul is created directly by God in each individual — souls do not evolve; they are immediately created — and that the conclusions of the natural sciences not be presented as established when they remain hypothetical.

The encyclical is stricter on the question of polygenism — the theory that the human race descended not from a single original pair (monogenism) but from multiple original ancestors. Polygenism, Pius XII teaches, cannot be reconciled with the Church’s teaching on original sin as set out by the Council of Trent. Trent had taught that original sin was transmitted from Adam to all his descendants by generation; this presupposes a single original pair from whom all human beings descend. Catholics, the encyclical states, do not enjoy the same liberty regarding polygenism that they enjoy regarding biological evolution more generally.

This teaching has remained controversial. Some theologians have argued that polygenism in a qualified form — multiple original lineages eventually contributing to a unified human population — may be reconcilable with monogenism in the theologically relevant sense (a single moral community in which Adam’s sin was transmitted). The discussion continues, but the doctrinal principle stated by Pius XII remains: any account of human origins must preserve the universal transmission of original sin from a real first parent.

Other Doctrinal Concerns

The encyclical addresses several further matters more briefly. The Mystical Body of Christ is identified with the Roman Catholic Church, against tendencies that would dissolve this identity (a reaffirmation of Mystici Corporis). The infallibility of the magisterium in non-defined teachings is reaffirmed: when the Holy Father in his ordinary teaching deliberately pronounces on a controverted matter, the question is no longer freely debated among theologians. The proper formation of seminarians in the Thomistic tradition is reaffirmed (echoing Aeterni Patris).

Theological Significance

Humani Generis did not stop the theological developments it addressed. Several of the figures associated with the nouvelle théologie — de Lubac, Daniélou, Congar — would become major influences at Vatican II just over a decade later, and several would be made cardinals. But the encyclical did establish doctrinal boundaries within which the conciliar theology was obliged to operate, and it ensured that the most radical positions among the new theologians were excluded.

The encyclical’s framework — reason’s capacity for truth, the proper use of philosophy in theology, the stability of dogmatic formulation, the doctrine of creation and of man — remains in force. Its principles have been invoked again and again in subsequent magisterial documents, most notably in Fides et Ratio (1998) and in various documents of the CDF. For Catholic theologians, Humani Generis is the indispensable companion to Pascendi in the magisterial diagnosis of modern theological error.

For the manual tradition on this site, the encyclical is the most important twentieth-century reaffirmation of the principles within which Pohle and Tanquerey worked. Its teaching on creation and on the human person directly underwrites their treatment of those tracts.