Heisenberg's Indetermination Principle and the Quantum

Leonard Eisenbud

Stephen G. Brush

Earle H. Kennard

The indetermination principle of Heisenberg is discussed and applied to cases where position and velocity of an electron are observed by allowing it to pass through shutters opened momentarily at known times. The principle requires that such a shutter shall change the speed of the electron in a manner that can only be predicted statistically, in the same way as the frequency of a light quantum passing through such a shutter must usually undergo alteration to correspond with the Fourier resolution of the finite train of waves that gets through while the shutter is open. This effect is small and hard to detect experimentally.

Ignacio Silva

Abstract When Werner Heisenberg presented his views of the fundamental indeterminism to which his uncertainty principle pointed in the basic levels of reality described by quantum mechanics, he used the Aristotelian technical terms of act and potency, affirming that the quantum system is in potency before the measurement and that the potency was actualised when the measurement took place, speaking thus of a ‘new ontology’ of quantum mechanics. I argue that Thomas Aquinas’ Aristotelian account of indeterminism in nature, through his analysis of the notions of matter as potency and form as act, can provide a suitable framework to understand Heisenberg's philosophical intuition about the nature of quantum systems.

Gilbert Newton Lewis, Joseph E. Mayer