“If a large diamond is cut up into little bits, it will lose its value just as…

Concept

Arguments are classified by the kind of inferential link that ties the premise to the conclusion. In an analogical argument that link is resemblance: a conclusion already accepted about one case is carried over to a second case because the two are alike in features taken to be relevant. Its strength therefore depends on how relevant and how numerous the shared features are, and never on logical necessity.

Applying it to this passage

The claim at issue concerns the diamond: divide it into little bits and its value falls. That claim is supported neither by data nor by a stated mechanism, but by setting it beside a second, separately accepted case in which an army divided into small units loses its strength. The connective "just as" marks that pairing, and the shared feature doing the work is that each is a whole whose worth or power is treated as depending on its remaining undivided. The conclusion about the diamond is therefore transferred from the army case on the strength of that resemblance, which is exactly the form of an analogical argument.

Contrasting the other argument types

• Deductive: here the premises would have to make the conclusion necessary, the way a general rule applied to a particular case does. Nothing said about armies logically compels any conclusion about diamonds, so the necessity is missing.

• Statistical: here the support would be numerical evidence drawn from a sample or a population, such as counts, proportions or averages. The passage offers no figures of any kind.

• Causal: here the support would be a cause-and-effect mechanism showing how dividing an object produces the loss. The passage asserts a parallel between two separate cases instead of establishing such a mechanism.

The argument is therefore analogical.