(from a convo with Claude AI)
This question actually splits into two quite different things: how theology approaches the study of morality, and the separate philosophical question of whether a moral failure invalidates a theologian’s ideas. Worth taking them one at a time.
How theology approaches morality
There’s no single method — traditions diverge sharply:
- Divine command theory: morality is grounded in God’s will or nature; something is good because God commands it (or reflects God’s character). Strong in much of Reformed and Islamic theology.
- Natural law: morality is discoverable through reason reflecting on human nature and its proper ends, independent of revelation — the dominant Catholic (Thomistic) approach, though it holds revelation completes and confirms it.
- Virtue ethics: focuses on character formation and practices that cultivate virtue over time, rather than rules or consequences — revived heavily in 20th-century Christian ethics (Alasdair MacIntyre, Stanley Hauerwas).
- Covenantal/relational ethics: morality flows from a relationship (covenant with God, discipleship, community) rather than abstract principle — you see this in Barth himself, and in much Jewish ethics.
- Situational/contextual ethics: right action depends on love or context applied to a specific situation rather than fixed rules (Joseph Fletcher, and more loosely present in Tillich’s existentialist theology).
Most working theologians blend several of these rather than picking one cleanly.
Does a theologian’s affair void their theology?
This is really an old question in a new outfit — it’s essentially the Donatist controversy from the 4th century. The Donatists argued that sacraments administered by a morally compromised priest (specifically, one who’d caved under persecution) were invalid. Augustine’s counter-argument, which became mainstream Christian doctrine, was that the validity of a sacrament or a truth doesn’t depend on the moral worthiness of the person conveying it — ex opere operato, “by the work worked,” not by the merit of the worker.
Applied to Barth and Tillich, a few distinct threads are worth separating rather than collapsing into one verdict:
- Logical validity vs. personal credibility. If Barth argues that grace is unconditional and irrevocable, that argument stands or falls on its own coherence and scriptural/philosophical grounding — not on whether Barth himself lived up to it. Judging an argument false because its author is a hypocrite is a version of the genetic fallacy. (Notably, both men lived several decades ago, so this connects to well-documented history rather than anything current — Barth’s decades-long domestic relationship with Charlotte von Kirschbaum alongside his wife Nelly is well attested in biographies, as are Tillich’s extramarital relationships, described candidly by his wife Hannah in her memoir.)
- Consistency and integrity as a separate question. It’s fair to ask whether a person’s life illustrates or contradicts their own theology, because that bears on how seriously to take their claim to have understood something existentially, not just intellectually. Some find it more troubling in Tillich’s case, since his theology of “acceptance despite unacceptability” and boundary-crossing existentialism arguably rationalized his behavior rather than sitting in tension with it — the ethics and the biography rhyme uncomfortably. Barth’s case reads differently to many: his theology doesn’t obviously excuse the relationship, which makes it more a personal failure than a philosophical one.
- Different Christian traditions answer this differently. Pastoral epistles (1 Timothy 3, Titus 1) make moral character a qualification for teaching/eldership — implying life and doctrine can’t be fully separated for someone in ongoing spiritual authority. More conservative and evangelical traditions tend to weight this heavily; the Catholic sacramental tradition (per Donatism) and much of academic theology weight it lightly, judging the work by its coherence rather than the author’s biography.
- A middle position many land on: the theology is evaluable independently, but the person’s authority to be trusted as a moral guide, pastor, or exemplar is legitimately damaged. You can hold “Church Dogmatics is a serious achievement worth engaging” and “Barth failed his wife and Charlotte badly, and that matters” at the same time without contradiction — they’re answering different questions.
Where do you fall on this — is your question more about whether their arguments hold up, or whether they had standing to make them?