Dualism (Indian philosophy)
Another form of dualism in Hindu philosophy is found in the Dvaita ("dualism") Vedanta school, which regards God and the world as two realities with distinct essences; this is a form of theistic dualism. By contrast, schools such as Advaita ("nondualism") Vedanta embrace absolute monism and regard dualism as an illusion ("maya").
Twin Earth thought experiment
Twin Earth is a thought experiment by philosopher Hilary Putnam, first in his paper "Meaning and Reference" (1973), and then in his paper "The Meaning of 'Meaning (1975), to illustrate his argument for semantic externalism, or the view that the meanings of words are ultimately not purely psychological. The "Twin Earth" thought experiment was one of three, the other two being the "Aluminum-Molybdenum", and the "Beech-Elm" cases. Since the publication of these cases, philosophers have proposed numerous variations on the experiment.