The period 1900–40 produced revolutionary developments in science and the arts. The rediscovery of the work of Gregor Mendel in 1900 revolutionized knowledge of hereditary transmission in showing that characteristics of organisms do not blend in offspring but are transmitted in discrete units according to specific laws, which ultimately became the foundation for modern scientific genetics. In The Interpretation of Dreams of 1900 Sigmund Freud laid the foundation for his theory of the mind as a network of unconscious processes and the residue of childhood psychosexual experience. Also in 1900, the introduction of Planck's constant to explain the spectra of thermal bodies was the first blow in a series of advances that led to a fully elaborated quantum theory by 1927. Most unsettling was the theory's indeterminacy principle, which put knowledge of subatomic events on a probabilistic basis, thereby limiting the strictly deterministic causality that classical physicists had posited throughout the universe. Albert Einstein's special relativity theory of 1905 maintained that space and time are not absolute and distinct but relative to motion and transform into one another. In 1908 Arnold Schoenberg composed music with no tonal center, while in 1911 Wassily Kandinsky painted no recognizable objects. No single literary change was as revolutionary as these others. However, the sum of formal innovations in the novel was revolutionary in providing new ways of rendering how people experience personal development, courtship conventions, family relations, urban life, national identification, imperial conquest, capitalist enterprise, liberal institutions, religious faith, and artistic creativity.