Facts are stubborn things

“Facts are stubborn things” is the principle that observed evidence can overrule theoretical expectation, expressed most explicitly when Professor Hardwigg points to the underground temperature and granite as facts that contradict Harry’s calculations. The phrase gathers several earlier disputes into a concise maxim, while the novel complicates it by showing both the value and the limits of confident scientific judgment.

The phrase in context

The expression appears in Professor Hardwigg’s reply to Harry’s calculations during their underground journey. Harry recalls that, by the geological limits he has learned, the Earth’s crust should be no more than sixteen leagues, or fifty miles, thick. He also expects a depth of about fifteen hundred leagues to produce a temperature of fifteen hundred degrees on the Réaumur scale, hot enough to melt granite. Hardwigg does not dispute Harry’s account of the scientific rule; instead, he directs attention to the granite that remains solid before them. He concludes that facts, as usual, are stubborn things and overrule theories.

The exchange distinguishes a prediction from an observation. Harry’s calculations are not presented as frivolous: they follow the accepted laws of increasing heat with depth. Yet the explorers’ actual surroundings do not match the predicted result. Hardwigg’s phrase names that discrepancy and insists that the material evidence cannot be dismissed simply because it conflicts with an established model.

A recurring clash over evidence and authority

The maxim resonates with Harry’s earlier objection to the expedition itself. After accepting that Saknussemm had found and identified an entrance into the Earth, Harry calls it madness to suppose that he or anyone else had followed the discovery. His reason is scientific teaching, theoretical and practical: descent into the Earth should expose the travelers to intolerable central heat. Hardwigg answers that he cares nothing for theories. The later appeal to stubborn facts therefore does not settle a single argument; it belongs to a repeated contest over whether inherited scientific expectations or immediate experience should govern their conclusions.

That contest also concerns who gets to interpret evidence. On the ascent toward Sneffels, Hardwigg explains that the behavior of the crater’s vapor spouts can indicate whether an eruption is imminent. If the steam remains in its habitual state, does not grow more energetic, and is not accompanied by oppressive atmospheric calm, he says there is no immediate danger. His confidence is grounded in observations and a proposed causal explanation, but he presents his judgment as authoritative, telling Harry that when science has issued its decision, it is to be heard and obeyed. The novel thus places the authority of scientific speech alongside the need to test claims against what can be observed.

Fossils and the limits of interpretation

The same friction emerges when Harry sees signs of ancient life in the passage walls. He recognizes the outlines of fucus and lycopods and picks up an almost perfect shell that appears to belong to an animal resembling a present-day form. Hardwigg continues forward with an apparently unaltered step; Harry suspects that his uncle has deliberately closed his eyes to what is visible. When Harry asks him to examine the shell, Hardwigg identifies it as belonging to an extinct crustacean of the trilobite order and insists that it proves no more than that.

The scene makes observation less conclusive than the slogan might suggest. Harry and Hardwigg confront material traces, but they do not agree on what those traces warrant them in concluding. The shell is evidence of an extinct animal; its significance for the larger question of life and geological history remains disputed. In this episode, the problem is not simply whether facts matter, but how far an observer may responsibly reason from them.

The phrase’s evidentiary force

Harry himself eventually accepts that the granite and the thermometer readings contradict his expected result. He says he is forced to yield to the evidence of his senses, while remaining surprised. That qualification matters: sensory evidence changes his position, but it does not erase the questions raised by the scientific rule he had applied. He considers an alternative explanation—that heat-resistant lava around the extinct volcanic chimney might conduct heat poorly and prevent the predicted increase from passing through its sides—and notes that the hot-water jet supports this view. Rather than continue an argument without decisive grounds, he resolves to take the facts as they stand.

“Facts are stubborn things” therefore functions as more than a declaration that observation defeats theory. The novel distinguishes seeing a result from explaining it: the solid granite and measured temperature challenge Harry’s calculation, while the hot-water jet and his proposed insulation hypothesis invite further interpretation. The phrase’s force lies in that tension. Evidence can compel a revision of expectation, but interpreting the evidence still requires reasoning, and the explorers’ underground discoveries repeatedly place accepted science under pressure without making every explanation immediately certain.