Obadiah Sedgwick’s Anatomy of Heresy

Introduction

Among the older Reformed divines, Obadiah Sedgwick is especially useful because he treats heresy directly, systematically, and pastorally in The Nature and Danger of Heresies. He is therefore the controlling historical guide for this series. His categories are fine enough to avoid careless overstatement and strong enough to judge destructive teaching.

Heresy in a broad and strict sense

Sedgwick notes that the word heresy can be used broadly for an opinion, a party, or a divisive doctrine. But he is interested in the strict theological sense. In that strict sense, heresy is not simply any false thought. It is a false doctrinal judgment held and advanced within the Christian profession that opposes a truth necessary to the faith.

This matters because some writers define heresy so broadly that every doctrinal mistake becomes heresy. Sedgwick refuses that inflation.

Error about the faith and error against the faith

Sedgwick distinguishes between errors about the faith and errors against the faith. An opinion may touch religious matters and yet not directly overthrow the faith. To be heresy in the strict sense, the error must be not only about revealed religion, but also against it in a way that strikes a necessary truth.

This distinction prevents flattening. An incorrect view of a difficult secondary issue may still be serious, but it is not necessarily heresy. By contrast, a doctrine that subverts Christ, the gospel, or the foundation by which the gospel is known is something else.

Fundamental doctrines

Sedgwick insists that the church must recognize fundamental truths—truths without which the Christian faith is not retained in its integrity. The denial of such truths is not a mere secondary defect. It is a wound to the body of faith.

In his treatment, the Trinity, the person of Christ, redemption through Christ, justification through Christ, and other necessary articles belong to this class. If a doctrine destroys them directly or necessarily, it is heresy in the strict sense.

Explicit heresy

Sedgwick recognizes direct or explicit heresy. This occurs when a doctrine openly denies a fundamental truth. Arian denial of Christ’s true deity is a classic example. A doctrine need not hide its intention to be judged heretical; some heresies come with open contradiction.

Reductive heresy or heresy by consequence

Sedgwick is especially helpful when he treats what may be called reductive heresy or heresy by consequence. Here a man may verbally retain a fundamental truth while embracing another proposition that necessarily overthrows it.

This is critical for bibliology. A man may say, “I affirm biblical authority,” while teaching a theory of the text that leaves the church without a present, authentic, providentially preserved rule. In that case he retains the orthodox phrase but hollows out its content.

Material doctrine and personal state

Sedgwick separates the nature of the doctrine from the state of the person. A proposition can be materially heretical because of its objective content and consequence. Yet the person uttering it may be mistaken, seduced, ignorant, or inconsistent. He becomes a formal heretic when he knowingly and obstinately persists in the doctrine.

This distinction must govern every later case study in this series.

The deceived and the obstinate

Sedgwick does not confuse the man newly drawn into error with the man hardened in it. A deceived believer may need careful instruction. An obstinate teacher who has been shown the truth and still spreads corruption must be dealt with differently. The presence of obstinacy is what moves the question from mere mistaken holding to formal heresy.

One fundamental denial is enough

A man may affirm many orthodox doctrines and yet deny one fundamental truth. Sedgwick insists that such a denial can be sufficient for heresy. Orthodoxy in many places does not cancel a destructive contradiction in one foundational place. This too is vital for textual controversies. A man may affirm the Trinity, the resurrection, and justification, yet undermine the very rule by which those doctrines are known.

Heresy and apostasy are not identical

Sedgwick distinguishes heresy from total apostasy. The apostate abandons Christianity as such. The heretic remains within Christian profession while corrupting some fundamental truth. This distinction matters pastorally. It explains why the church addresses the heretic as one who has not fully cast away Christian profession, yet whose teaching is deadly.

Conclusion

Sedgwick gives the church a disciplined way to think. Not every error is heresy. Heresy concerns fundamental truth. Some heresies are direct, while others work by consequence. A doctrine may be materially heretical before its present advocate has been shown to be a formal heretic. These distinctions will govern the rest of the series.

What this article proves

It proves that the older Reformed use of heresy was careful, technical, and fundamentally connected to necessary articles of the faith.

What this article does not yet prove

It does not yet show how Calvin, Whitaker, and Turretin relate to Sedgwick’s formulation. That follows next.