An analogy is a type of reasoning, and as such is referred to the logician for more precise definition. His briefest explanation of the term may be stated as the inference of a further degree of resemblance from an observed degree of resemblance; the argument that because the Earth and Mars agree in the common possession of a solid crust, an atmosphere, presence of water, changes of season, the possibilities of rain and snow, and other observed qualities, they will also agree in the further respect of being inhabited. This may serve as an exemplar of the analogical argument in its purest and most developed form; but in the survey of the varieties and distribution of this natural product of rationality, it will be necessary to include many forms of thought diverging more or less from, though always retaining, a recognizable relation to this type. The analogical inference, indeed, goes back to an inarticulate form, in which it merges into a feeling rather than an argument, a susceptibility to an influence supported by undefined plausibility, rather than a conclusion from tangible evidence. But however lacking in definiteness or formulation, however unconsciously realized and barely expressible, the tendency or disposition to believe is communicated to others and becomes an influential factor in the ultimate fixation of belief and in the guidance of conduct. Logically considered, analogy is always a weak argument; and becomes weaker, as the range of observed resemblance is more and more limited, as the resemblances belong to accidental, unessential traits, and as the underlying basis of the inference is removed from direct verification. Psychologically, its power to influence belief may be very strong, and when this is not the case, there still may exist a disposition to be influenced by analogical considerations, even when these are successfully resisted or suppressed. The instinctive proclivity towards the use of analogies, whether it be logical or anti-logical in effect, forms an interesting psychological trait. Logic counsels how we may think most profitably and correctly; psychology describes how we actually do think or tend to think. The logician is the gardener bent upon training certain selected flowers according to an ideal standard, and eradicating all others as weeds; while the psychologist is the botanist to whom all plants, weeds, and flowers alike are worthy objects of study, and who, indeed, traces significant resemblances between the despised weed and the choice flower.
The natural history account of analogy will consider the status in less advanced stages of human development, and the evolution of this form of thought, which scientists to-day use only with the greatest caution, and to which they at best assign but a limited and corroborative value. It will appear that analogy is dominant in primitive types of thought; that it has an important cultural history; and has left an unmistakable impress upon many beliefs of our civilization, marked as obsolete, perhaps, in the dictionary of the cultured, but current still in the parlance of average and untutored humanity.
II
The great law of apperception, teaching that we observe according to our inherited capacities and our acquired experience, that we in a very real sense create the world in which we live, explains the difficulty of realizing modes of thought strikingly different from our own, either as more primitive, or more complex, or as based upon other perspectives of the social, intellectual, and ethical rules that guide thought and conduct. To the supremely civilized citizen of the nineteenth century, the mental life of one who has hardly a firm hold on the first round of the ladder of civilization is naturally somewhat incomprehensible. An illustration of the conspicuous contrast, though doubtless amidst an inherent community, of the thought-habits of untutored and of cultured man, may suggest the direction and the nature of the evolutionary development that separates, yet binds, the one and the other. Prominent among such contrasts is the different standing assumed by the facts and reasonings of science in primitive and in highly civilized life; and an important part of this difference may be viewed as the shifting of the position occupied by the argument by analogy. Deeper than the language of words, and underlying their use and formation, is the habit of comparing object with object, of tracing resemblances and noting contrasts. It would seem that in the primitive use of this process there is lacking the distinction between the resemblances more strictly inherent in the objects and those originating in the mode of viewing them; subject and object are still merged in a vaguer realm of perception where myth and science, poetical fiction and evident fact, are as yet undifferentiated and mingle without let or hindrance. The savage frames his world by the realization of simple fancies suggested by slight analogies, where the man of culture examines the objective causes of phenomena under the guidance of scientifically established principles and accurate logic. Fortunately, however, for our power of realizing bygone mental traits, these forms of belief still find currency as survivals, in Mr. Tylor's apt words, "of the lower culture which they are of to the higher culture which they are in." We thus can understand the belief we no longer share; we can appreciate as suggestive myth or far-fetched analogy what to our ancestors may have been a plausible belief or a satisfactory explanation.
The prominence of analogy among undeveloped peoples supplies unlimited illustrations of the rôle which it plays in primitive circles, the essential influence which it exerts over thoughts and customs in the early history of mankind. Consider first that widespread class of customs and observances by which the savage regards himself as influencing for good or ill the fate of friend or foe. The Zulu chewing a bit of wood to soften the heart of the man he wishes to buy oxen from, or of the woman he is wooing (Tylor); the Illinois Indians making figures of those whose days they desire to shorten, and stabbing these images to the heart, or by performing incantations upon a stone trying to form a stone in the hearts of their enemies (Dorman); the Peruvian sorcerer, making rag dolls and piercing them with cactus-thorns, and hiding them about the beds to cripple people; or the native of Borneo, making a wax figure of his enemy in the belief that as the image melts, the enemy's body will waste away (Tylor); the Zulu sorcerer who secures a portion of a desired victim's dress and buries it secretly, so that, as it rots away, his life may decay (Clodd); the confession recorded in a seventeenth-century trial for witchcraft, that the accused had "buried a glove of the said Lord Henry in the ground, so that as the glove did rot and waste, the liver of the said lord might rot and waste" (Brand); the New Britain sorcerer of to-day who burns a castaway banana skin, so that he who carelessly left it unburied may die a tormenting death (Clodd); bewitching by operating upon a lock of hair or the parings of the finger-nails, and the consequent widespread custom of religiously preventing such personal scraps from falling into others' possession;—all these varied forms of primitive witchcraft rest upon the notion that one kind of connection, one link of resemblance, will bring with it others. The argument, if explicitly stated, as can hardly be done without doing violence to its instinctive force, may be put thus: this bit of wood or stone or lock of hair or scrap of clothing resembles this man or woman in that the one represents the other or that the one had a personal connection with the other; therefore they will further resemble one another in that whatever will make the one soft and yielding or the other hard and unfeeling will have the same effect on the other, or in that whatever is done to the one will happen to the other. Other considerations combine with this underlying analogical factor to impart cogency and plausibility to a belief or custom; but the type of the logic, crooked though it be, is recognizable throughout.
Another significant group of primitive beliefs, involving a similarly indirect argument by analogy, relates to the partaking of an animal for the sake of thus absorbing its typical qualities. The Malays eat tiger to acquire the sagacity as well as the cunning of that animal; the Dyaks refuse to eat deer for fear of becoming faint-hearted; the Caribs eschew pigs and tortoises for fear of having their eyes grow small (Lubbock); even cannibalism may be indulged in, in the hopes of absorbing the courage of a brave man, as in the case of Captain Wells, who was killed near Chicago in 1812, and whose body was cut up and distributed among the Indians, "so that all might have the opportunity of getting a taste of the courageous soldier" (Clodd); and in an ancient Mexican rite, called the eating of the god, there occurs an elaborated and symbolical form of the same belief.
The use of omens, the interpretation of signs and coincidences, forms another rich field for illustration of arguments by analogy. "Magical arts," says Mr. Tylor, "in which the connection is that of mere analogy or symbolism, are endlessly numerous throughout the course of civilization. Their common theory may be readily made out from a few typical cases, and thence applied confidently to the general mass. The Australian will observe the track of an insect near a grave to ascertain the direction where the sorcerer is to be found by whose craft the man died.... The Khondi sets up the iron arrow of the war god in a basket of rice, and judges from its standing upright that war must be kept up also, or from its falling that the quarrel may be let fall too; and when he tortures human victims sacrificed to the earth goddess he rejoices to see them shed plentiful tears, which betoken copious showers to fall upon his land." "In the burial ceremonies of the natives of Alaska, if too many tears were shed they said that the road of the dead would be muddy, but a few tears just laid the dust" (Dorman). "The Zapotecs had a very curious manner of selecting a manitou for a child at its birth. When a woman was about to be delivered, the relatives assembled in the hut and commenced to draw on the floor figures of different animals, rubbing out each one as fast as completed. The one that remained at the time of the birth was called the child's second self, and as soon as grown up he procured the animal, and believed his health and existence bound up with it" (Dorman). The taking of omens by the flight of birds or the tracks of animals, by the sky, by the inspection of sacrifices, by the trivial happenings of daily life, abound in savage ceremonials, and in a fair proportion of cases carry with them the rationale of their origin, that saves them from being mere caprice. And in all those endless appeals to chance or lot for the detection of crime, the unfoldment of the future, the prediction of the issue of disease or of important tribal events, there is always some underlying link of connection between the kind of omen or the nature of its interpretation and the issue it signifies; and this connection it is, however slight or fanciful, that maintains the belief in the further bond of omen and issue.
III
That such connections may travel still farther along the path of analogy without losing force, is well illustrated in the observances regarding the use of names. The connection seems to pass from thing to image, to name, much as picture-writing passes into word-writing. The use of idols is abundant evidence of the extent of this mental operation; what is done to or for the idol is analogically transferred to the god, and the confusion may become so gross that when the oracles of two gods disagree, their idols are knocked against each other, and the one that breaks is declared in the wrong. A drawing or other rough resemblance may do service for the thing, especially in sacrifices of objects of value. By similar steps the name becomes an essential portion of the object or person named, and analogies formed through the name are applied to the thing. Accordingly, a man may be bewitched through his name; hence there arise the most elaborate and rigid observances prohibiting the use of the name, which are grouped together in the complex code of the Taboo,—that "dread tyrant of savage life, ... the Inquisition of the lower culture, only more terrible and effective than the infamous 'Holy Office'" (Clodd). For uncomplicated illustrations of name analogies, however, we must go to other customs than the Taboo. It is related that in the British war with Nepaul, Goree Sah had sent orders to "find out the name of the commander of the British army; write it upon a piece of paper; take it some rice and turmeric; say the great incantation three times; having said it, send for some plum-tree wood, and therewith burn it;" thus was the life of the commander to be destroyed. Similarly it was suspected that the King of Dahomey refused to sign a letter, written in his name to the President of the French Republic, for fear that M. Carnot might bewitch him through it (cited by Clodd). "Barbaric man believes that his name is a vital part of himself, and therefore that the names of other men and of superhuman beings are also vital parts of themselves. He further believes that to know the name is to put its owner, whether he be deity, ghost, or mortal, in the power of another, involving risk of harm or destruction to the named. He therefore takes all kinds of precautions to conceal his name, often from his friend, and always from his foe" (Clodd). In Borneo the name of a sickly child is changed to deceive the evil spirits that torment it. "When the life of a Kwapa Indian is supposed to be in danger from illness, he at once seeks to get rid of his name, and sends to another member of the tribe, who goes to the chief and buys a new name, which is given to the patient. With the abandonment of the old name it is believed that the sickness is thrown off. 'On the reception of the new name the patient becomes related to the Kwapa who purchased it. Any Kwapa can change or abandon his personal name four times, but it is considered bad luck to attempt such a thing for the fifth time'" (Clodd). The Mohawk chief can confer no higher honor on his visitor than by giving him his name, with which goes the right of regarding the chief's fame and deeds of valor as his own. A Tahitian chief became so smitten with Stevenson's charms that he assumed Stevenson's name; in exchange Stevenson took the name of the chief, and in one of his letters signs himself, "Teritera, which he was previously known as Robert Louis Stevenson." When totem and tribal names are assumed to obtain the qualities of the animal namesake, or the reverence due to the person is transferred to the name, and when incantations and the utterances of mystic formulæ are granted like efficacy as the manipulation of the things themselves, we see the operation of the mental law under discussion; though it is still more saliently illustrated in the more artificialized practices of the Chinese physician, who, for lack of a desired drug, will "write the prescription on a piece of paper and let the sick man swallow its ashes or an infusion of the writing in water;" or of the Moslem who expects relief from a decoction in which a verse of the Koran written on paper has been washed (Tylor).