The conclusion of Heisenberg based on quantum mechanical theory that the precise position of a specific electron in an atomic orbit cannot be determined and that consequently the ultimate nature of matter is not susceptible to objective measurement. The result of this concept was development of the orbital theory in which electron behavior is dealt with on a statistical basis. Its validity was confirmed by 1930 by the work of other mathematical physicists such a DeBroglie, Fermi, and Schrodinger.See Orbital Theory; Heisenberg, Werner P..