Up to now sculptors have preferred the mass and neglected or paid little attention to such an important component of mass as space … we consider it as an absolute sculptural element. I do not hesitate to affirm that the perception of space is a primary natural sense which belongs to the basic senses of our psychology
In: Herschel Browning Chipp (1968) Theories of Modern Art. p. 332 - Sculpture: Carving and Construction in Space (1937)