In the twelfth paragraph of his essay “The Method of Scientific Investigation,” T. H. Huxley sums up an analogy he has employed in the preceding paragraphs – an analogy in which he compares the investigation of a hypothetical robbery to the methods by which scientists establish relationships of causes and effects. The steps by which Huxley develops this analogy include the following:
- He describes the scene of an apparent burglary.
- He shows how instantly we make the leap from the detailed physical evidence to the conclusion that a burglary has indeed occurred.
- He argues that the immediate assumption that a burglary has occurred is in fact merely a hypothesis.
- He then breaks the hypothesis down into its component parts, which involve both induction and deduction.
- He shows how convincing the hypothesis seems even if every single detail of fact is not absolutely known.
- He argues that the hypothesis is not proven but is only highly plausible.
- He imagines the arrival of various friends who dispute the hypothesis, offering alternative explanations that do not seem very plausible.
- He imagines that a burglar is apprehended and that all the resulting evidence suggests that the original hypothesis was correct.
- He then concludes that the process of reasoning used in assessing the hypothetical burglary is
exactly the same train of reasoning as a man of science pursues when he is endeavouring to discover the origin and laws of the most occult phenomena.
- He notes that scientific hypotheses must be much more rigorous than the hypotheses used in everyday life and involving common, everyday matters. This is because mistakes in scientific hypotheses can have more serious consequences than mistakes made in everyday reasoning about common and relatively inconsequential matters.
- He argues that scientific hypotheses should be well-informed and plausible rather than based on mere guess-work or fantasies.
- He argues that the value of a hypothesis will depend largely on the care with which it is formulated.
Most people have found the analogy Huxley uses here to be effective and persuasive. Evidence for this conclusion includes the following:
- Huxley’s essay is widely reprinted.
- Huxley’s essay is widely reprinted in texts intended to be read by students with no special expertise in science. Such reprintings would be irresponsible if Huxley’s arguments were widely doubted.
- Huxley himself is regarded as one of the major figures of 19th-century intellectual life; this would probably not be the case if one of his major essays were subject to serious doubt or dispute.
- Huxley was a major proponent of Darwinism, and Darwin’s ideas are now among the most widely accepted ideas ever put forward as scientific hypotheses. Indeed, the present analogy is obviously relevant to the case for Darwinism. If this particular argument by Huxley were flawed, Huxley’s larger case for Darwinism would also be flawed. Instead, that case has seemed convincing to most scientists.
- For all these reasons, it seems unlikely that the analogies made by Huxley here are the subject of widespread scientific dispute.