Development of Quantum Mechanics

Is light a wave or a particle?

[…] when we allow for the dynamics of gravity and quantum mechanics, we find that [our] commonsense notion is no longer true. This is the beauty of science, and it should not be threatening. Science simply forces us to revise what is sensible to accommodate the universe, rather than vice versa.

—Lawrence Krauss, A Universe From Nothing [Krauss, 2012, p. 151]

Quantum mechanics could just as well be called “wave mechanics” [cf. Bell, 1988, p. 187]. That is to st...