Just as melting ice-cubes do not cause a glass of water to overflow, melting…

Concept: An analogical argument reasons from resemblance. Two cases are known to be alike in certain relevant respects; a property is observed in the first case; that property is therefore extended to the second. Its conclusion is probable rather than necessary, and its strength depends on how relevant and extensive the shared features are.

Application: The two cases set side by side are an ice-cube floating in a glass of water and sea-ice floating on the ocean. The resemblance the argument leans on is physical: floating ice already displaces a mass of water equal to its own, so in the glass the meltwater essentially refills the space the ice had occupied below the waterline and the level stays put. That property of the familiar case is then carried across to the parallel case, giving the conclusion that melting sea-ice does not raise oceanic volume. The transfer is only ever as good as the resemblance: sea-ice meltwater is far less saline, and therefore less dense, than the seawater it displaced, so the real-world effect is very small rather than exactly zero. That is characteristic of analogical reasoning, which moves from one case to a like case and yields a probable conclusion rather than a guaranteed one.

Cross-check: The remaining classifications name different premise structures:

• A hypothetical argument rests on a supposition, standardly of the form "if P, then Q", whereas both cases here are asserted as fact rather than entertained as a condition.

• A psychological argument grounds its premises in mental states such as motives, beliefs or feelings, while both premises here concern the physical behaviour of water and ice.

• A statistical argument moves from numerical data about a sample to a claim about a wider population, and no frequency, proportion or sample appears in the stem.

The argument is therefore analogical: a property established in one case is transferred to a second case on the strength of a stated resemblance between them.