analogy

1. 5. Analogy.
The argument from analogy is founded on a resemblance of relations, while ordinary examples are founded on a direct resemblance. There is an analogy between the human heart and a great city, and hence it has been argued that when the size of a city is greatly increased its functions are impaired. The argument for the inhabitation of the planets is of this kind, since they resemble the earth in their general relations, though not in all particulars. The argument from analogy has great force in winning the assent of superficial thinkers, but its logical analysis reveals the danger of depending upon it, unless confirmed by collateral proofs. (Hill)