Page:An Enquiry Concerning Human Understanding - Hume (1748).djvu/178

 act a Similarity, the Analogy is less perfect, and the Inference is less conclusive; tho' still it has some Force, in Proportion to the Degrees of Similarity and Resemblance. The Anatomical Observations, form'd upon one Animal, are, by this Species of Reasoning, extended to all Animals; and 'tis certain, that when the Circulation of the Blood, for Instance, is prov'd clearly to have place in one Creature, as a Frog or Fish, it forms a strong Presumption, that the same Principle has place in all of them. These analogical Observations may be carry'd farther, even to this Science, of which we are now treating; and any Theory, by which we explain the Operations of the Understanding or the Origin and Connexion of the Passions, in Man, will acquire additional Authority, if we find, that the same Theory is requisite to explain the same Phænomena, in all other Animals. We shall make Trial of this, with regard to the Hypothesis, by which, in the foregoing Essays, we have endeavour'd to account for all experimental Reasonings; and 'tis hop'd, that this new Point of View will serve to confirm all our former Observations.

First. It seems evident, that Animals, as well as Men, learn many Things from Experience, and infer,