Interpretation of electron diffraction in terms of wavefunctions posits the wave-particle duality of matter.  
Interpretation of electron diffraction in terms of wavefunctions posits the wave-particle duality of matter.  Heisenberg's uncertainty principle extends this to commuting observables. Neils Bohr developed what quantum  mechanical principle to this phenomenon a statement of which appears on his coat of arms.
Interpretation of electron diffraction in terms of wavefunctions posits the wave-particle duality of matter.  
Principle of Complementarity