Why an author can rationally believe every line in their book is true—and false
In 1965, philosopher D. C. Makinson outlined the Preface Paradox. An author painstakingly verifies every statement in their book, having rational justification for each claim. Yet, recognizing human fallibility, they write in the preface: 'Any remaining errors are entirely my own.' Logically, the author rationally believes every individual claim is true, while simultaneously believing the book as a whole contains at least one false statement.
The Anatomy of the Author's Dilemma
In 1965, Australian philosopher David C. Makinson published a brief paper in the journal Analysis that introduced a problem now central to epistemology: the Preface Paradox. Makinson asked readers to consider an author who has written a massive, detailed work of nonfiction, such as a comprehensive history book. For every single factual claim made across hundreds of pages, the author has carefully reviewed the evidence, checked primary sources, and concluded that the claim is well-justified. The author rationally believes that claim one is true, claim two is true, and so on for every individual sentence in the manuscript.
However, before sending the work to press, the author crafts a standard preface. Aware of the historical reality that even the most meticulous researchers make mistakes, the author writes a modest disclaimer: 'Any errors that remain are entirely my own.' In doing so, the author is not offering empty rhetoric; they genuinely and rationally believe that somewhere in the vast collection of assertions, at least one error exists. This creates a strange situation: the author rationally believes statement one, rationally believes statement two, and rationally believes every statement up to the end, while simultaneously holding the rational conviction that not all of these statements are true together.
The Logical Collision
The problem exposed by the preface paradox is not merely an emotional clash between pride and humility; it represents an explicit logical contradiction. If an author holds a set of individual beliefs—let us label them s₁, s₂, s₃, up to sₙ—they are committed to the truth of each individual proposition. At the same time, the admission in the preface asserts that at least one of these propositions is false, which can be formally represented as the negation of their conjunction: not-(s₁ and s₂ and s₃ ... and sₙ).