Comparative mythology is the comparison of myths from different cultures in an attempt to identify shared themes and characteristics. Comparative mythology has served a variety of academic purposes. For example, scholars have used the relationships between different myths to trace the development of religions and cultures, to propose common origins for myths from different cultures, and to support various psychoanalytical theories.
The comparative study of mythologies reveals the trans-national motifs that unify spiritual understanding globally. The significance of this study generates a "broad, sympathetic understanding of these "stories" in human history". The similarities of myths remind humanity of the universality in the human experience.
Background
Anthropologist C. Scott Littleton defined comparative mythology as "the systematic comparison of myths and mythic themes drawn from a wide variety of cultures". By comparing different cultures' mythologies, scholars try to identify underlying similarities and/or to reconstruct a "protomythology" from which those mythologies developed. To an extent, all theories about mythology follow a comparative approach—as scholar of religion Robert Segal notes, "by definition, all theorists seek similarities among myths". However, scholars of mythology can be roughly divided into particularists, who emphasize the differences between myths, and comparativists, who emphasize the similarities. Particularists tend to "maintain that the similarities deciphered by comparativists are vague and superficial", while comparativists tend to "contend that the differences etched by particularists are trivial and incidental".
Comparative approaches to mythology held great popularity among eighteenth- and nineteenth-century scholars. Many of these scholars believed that all myths showed signs of having evolved from a thought which interpreted nearly all myths as poetic descriptions of the sun's behavior. According to this theory, these poetic descriptions had become distorted over time into seemingly diverse stories about gods and heroes. However, modern-day scholars lean more toward particularism, feeling suspicious of broad statements about myths. A recent exception is the historical approach followed in E.J. Michael Witzel's reconstruction of many subsequent layers of older myths.
Approaches
Comparative mythologists come from various fields, including folklore, literature, history, linguistics, and religious studies, and they have used a variety of methods to compare myths.
Linguistic
Some scholars look at the linguistic relationships between the myths of different cultures. For example, the similarities between the names of gods in different cultures. One particularly successful example of this approach is the study of Indo-European mythology. Scholars have found striking similarities between the mythological and religious terms used in different cultures of Europe and India. For example, the Greek sky-god Zeus Pater, the Roman sky-god Jupiter, and the Indian (Vedic) sky-god Dyauṣ Pitṛ have linguistically identical names.
This suggests that the Greeks, Romans, and Indians originated from a common ancestral culture, and that the names Zeus, Jupiter, Dyaus and the Germanic Tiu (cf. English Tues-day) evolved from an older name, *Dyēus ph2ter, which referred to the sky-god or, to give an English cognate, the divine father in a Proto-Indo-European religion. An approach which is both historical and comparative was recently proposed by E.J. Michael Witzel. He compares collections of mythologies and reconstructs increasingly older levels, parallel to but not necessarily dependent on language families. The most prominent common feature is a storyline that extends from the creation of the world and of humans to their end. This feature is found in the northern mythologies of Eurasia and the Americas ("Laurasia") while it is missing in the southern mythologies of Subsaharan Africa, New Guinea and Australia ("Gondwanaland").
Mythological phylogenies also are a potentially powerful way to test hypotheses about cross-cultural relationships among folktales.