Law of Parsimony

The Law of Parsimony is the principle that, when several explanations are possible, the simplest is usually correct. In the investigation beneath the Milne Ice Shelf, Rachel uses it to resist accepting Norah Mangor’s categorical dismissal of frozen plankton as an explanation for the mysterious phenomenon. The principle gives Rachel a method for weighing the evidence, but it does not by itself settle whether her suspicion is right.

Definition and Application

Rachel recalls the rule as an instinctive result of her training at the National Reconnaissance Office: when multiple explanations exist, the simplest is usually correct. Faced with an anomaly in the glacier, she finds frozen plankton to be the most economical explanation. Her reasoning is not presented as proof; it is a guide for choosing among explanations while the evidence remains unsettled.

Conflict with Norah’s Account

Norah says that brine interstices occur only in seasonal ice, which forms and melts each season, whereas the Milne Ice Shelf consists of fast ice that forms in the mountains and remains fixed until it migrates to the calving zone and falls into the sea. On that basis, she rules out hidden networks of frozen plankton in the glacier. The group falls silent, but Rachel’s application of parsimony does not yield to Norah’s authority: she continues to regard plankton as the simplest solution to the riddle.

Suspicion and Uncertainty

The disagreement becomes more than a choice between scientific explanations. Rachel considers whether Norah might have seen plankton, recognized that her claim of solid glacier ice was mistaken, and now be trying to cover her tracks. The account presents this as Rachel’s suspicion, not an established fact. The principle helps her keep an alternative explanation in view, while the possibility of professional self-protection makes the evidence and its interpretation harder to separate.

Consequences for the Investigation

Rachel’s concern reaches beyond the immediate anomaly because she has just briefed the White House staff that the meteorite was discovered in pristine ice, untouched by outside influence since 1716, when it broke away from the famous Jungersol meteorite. If the ice’s supposedly sealed condition is in question, so too is an important part of the account she has presented. The Law of Parsimony therefore operates here as a prompt to reconsider the assumptions behind a consequential claim, not as a guarantee that the simplest available explanation is true.