Ockham's Razor

Occam’s razor is Christopher’s name for a rule of explanation: do not presume more things to exist than are necessary. He uses it to argue for ordinary, evidence-based accounts of apparent mysteries, linking the principle to both Wellington’s murder and photographs of fairies. Its significance lies not only in its concise formula but also in the contrast it draws between looking closely at evidence and choosing to believe what one wants to be true.

Definition and Form

Christopher introduces the principle as a law, not a physical razor. He first gives its Latin formulation, “Entia non sunt multiplicanda praeter necessitatem,” and then translates it as “No more things should be presumed to exist than are absolutely necessary.” The translation unfolds across several lines, giving the rule the form of a definition before Christopher turns to examples of how it applies.

The wording is deliberately restrictive: an explanation should not multiply assumptions beyond what the evidence calls for. Christopher’s examples make the abstract maxim practical. Rather than treating the unexplained as proof of extraordinary causes, he looks for an account that requires fewer unsupported premises.

The Fairies Photographs

The principle follows Christopher’s account of photographs that some people accepted as evidence of real fairies. Sir Arthur Conan Doyle had said in an article in The Strand that he believed the pictures were genuine. Christopher challenges that belief by attending to what the images show: the fairies resemble illustrations in old books, complete with wings, dresses, tights, and shoes. Their familiar, storybook appearance makes a fabricated explanation more plausible to him than the existence of photographed fairies.

A later account supplies a concrete explanation for the images. In 1981, Joe Cooper interviewed Elsie Wright and Frances Griffiths for The Unexplained. Wright said that all five photographs had been faked; Griffiths said that four had been faked but one was real. They also said that Wright had drawn the fairies from Princess Mary’s Gift Book by Arthur Shepperson. Christopher presents these differing statements as part of the evidence surrounding the photographs, while his broader point is that people may resist the truth even when a simpler explanation is available.

Application to Murder

Christopher applies the same reasoning to murder, stating that a victim is usually killed by someone known to them. In the context of his investigation into Wellington’s murder, the proposition directs attention toward a familiar person rather than an elaborate or supernatural explanation. It is a general rule of likelihood, not, by itself, proof of who committed a particular crime.

That distinction is essential to the principle as Christopher presents it. Occam’s razor favors an explanation that does not require unnecessary assumptions, but it does not make an unverified conclusion certain. Its value depends on the relationship between a proposed explanation and the evidence available to support it.

Truth, Evidence, and Belief

Christopher explicitly connects the principle to the claim that people sometimes do not want to know the truth. His criticism of belief in the fairy photographs is therefore also a criticism of how people handle evidence: an appealing idea can persist even when the details invite a more ordinary explanation. The contrast is between examining what is actually present and protecting a preferred belief from scrutiny.

The principle joins two apparently different subjects—fairies and murder—through one method of reasoning. In each case, Christopher seeks an explanation that does not depend on adding entities or causes for which there is no need. His examples give Occam’s razor its practical force: it is a discipline of attention, requiring that explanations remain answerable to what can be observed and established.