Cosmology of Tolkien's legendarium

The cosmology of J. R. R. Tolkien's legendarium combines aspects of Christian theology and metaphysics, mythology (especially Germanic mythology) and pre-modern cosmological concepts in the flat Earth paradigm with the modern spherical Earth view of the solar system.

Tolkien's cosmology is based on a clear dualism between the spiritual and the material world. While the Ainur, the first created but immaterial angelic beings have the "subcreative" power of imagination, the power to create independent life or physical reality is reserved for Eru Ilúvatar (God); this power of (primary) creation is expressed by the concept of a "Secret Fire" or "Flame Imperishable". The term for the material universe is Eä, "the World that Is", as distinguished from the purely idealist pre-figuration of creation in the minds of the Ainur. Eä contains our Earth (and solar system) in a mythical ancient past, of which Middle-earth is the main continent. Eä (Quenya for "let [these things] be!") was the word spoken by Eru Ilúvatar (metaphorically, in the purported Quenya-language account of creation) by which he brought the physical universe into actuality.

The legendarium examines the possibility of alternative theologies, in the sense of exotheology, by postulating immortality (via reincarnation) for the Elves, contrasting with the fate of Men, who remain subject to mortality.

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