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. Structural Some scholars look for underlying structures shared by different myths. The folklorist Vladimir Propp proposed that many Russian fairy tales have a common plot structure, in which certain events happen in a predictable order. In contrast, the anthropologist Claude Lévi-Strauss examined the structure of a myth in terms of the abstract relationships between its elements, rather than their order in the plot. In particular, Lévi-Strauss believed that the elements of a myth could be organized into binary oppositions (raw vs. cooked, nature vs. culture, etc.). He thought that the myth's purpose was to "mediate" these oppositions, thereby resolving basic tensions or contradictions found in human life or culture. Psychoanalysis Some scholars propose that myths from different cultures reveal the same, or similar, psychoanalytic forces at work in those cultures. Some Freudian thinkers have identified stories similar to the Greek story of Oedipus in many different cultures. They argue that these stories reflect the different expressions of the Oedipus complex in those cultures. Likewise, Jungians have identified images, themes, and patterns that appear in the myths of many different cultures. They believe that these similarities result from archetypes present in the unconscious levels of every person's mind. Motifs Comparative mythology has uncovered a number of motifs, shared elements, between the bodies of myths of different peoples, including some very