The authors of model-dependent realism claim that what type of theory may not exist?
The Grand Design (book) The Grand Design is a popular-science book written by physicists Stephen Hawking and Leonard Mlodinow and published by Bantam Books in 2010. The book examines the history of scientific knowledge about the universe and explains 11 dimension M-theory. The authors of the book point out that a Unified Field Theory (a theory, based on an early model of the universe, proposed by Albert Einstein and other physicists) may not exist.
Noumenon In metaphysics, the noumenon ( , , from Greek: [εν]νοούμενον) is a posited object or event that exists without sense or perception. The term "noumenon" is generally used in contrast with or in relation to "phenomenon", which refers to anything that can be apprehended by or is an object of the senses. Modern philosophy has generally been skeptical of the possibility of knowledge independent of the senses, and Immanuel Kant gave this point of view its canonical expression: that the noumenal world may exist, but it is completely unknowable through human sensation. In Kantian philosophy, the unknowable noumenon is often linked to the unknowable "thing-in-itself" (in Kant's German, "Ding an sich"), although how to characterize the nature of the relationship is a question yet open to some controversy.