The exhibition of both wavelike and particlelike properties by a single entity, as of both diffraction and linear propagation by light.
The exhibition of both wavelike and particlelike properties by a single entity. For example, electrons undergo diffraction and can interfere with each other as waves, but they also act as pointlike masses and electric charges. The theory of quantum mechanics is a attempt to explain these apparently contradictory properties exhibited by matter.
The inherent contradiction in the way energy behaves. At the turn of the 20th century, it was believed that light was electromagnetic waves and electrons were particles. By the 1930s, it was determined that light behaves as if it were made up of particles (photons) as well as waves, and electrons also behave like waves. This has driven scientists to drink and is one of the most puzzling phenomena in the universe. See quantum mechanics.