I. A marine animal of the maggot form. | II. Group of lowly-organized fishes. | III. Ganoids and other fishes. | IV. The Amphibians. | V. The ancient Marsupials. | VI. The Quadrumana and all the higher mammals. | VII. The Lemuridæ. | VIII. The Simiadæ. | +-------------------+ | | IX. Old World Monkeys. New World Monkeys. | X. Man. These ten classes or groups of animals are supposed to be connected together by intermediate diversified forms, which constitute the transitions from one of the classes or groups to the other; and in reading the table downward it must be remembered that we are reading in fact through an ascending scale of beings, from the very lowest organized creature to the highest. The whole, taken together, forms a chain of evidence; and, according to the rational rules of evidence, each distinct fact ought to be proved to have existed at some time before our belief in the main hypothesis can be challenged. I know of no reason why the probable truth of a scientific hypothesis should be judged by any other rules of determination than those which are applied to any other subject of inquiry; and, while I am ready to concede that in matters of physical science it is allowable to employ analogy in constructing a theory, it nevertheless remains, and must remain, true that where there are numerous links in a supposed chain of proofs that are established by nothing but an inference drawn from an analogous fact, the collection of supposed proofs does not exclude the probable truth of every other hypothesis but that which is sought to be established, as it also does not establish the theory in favor of which the supposed facts are adduced. Upon these principles of evidence I propose now to examine the Darwinian pedigree of man.