nLab potentiality and actuality




Quantum systems

quantum logic

quantum physics

quantum probability theoryobservables and states

quantum information

quantum computation


quantum algorithms:

quantum sensing

quantum communication




In classical physics

The solution of the difficulty that is raised about the motion — whether it is in the movable — is plain. It is the fulfilment of this potentiality, and by the action of that which has the power of causing motion; and the actuality of that which has the power of causing motion is not other than the actuality of the movable, for it must be the fulfilment of both. A thing is capable of causing motion because it can do this, it is a mover because it actually does it. But it is on the movable that it is capable of acting. Hence there is a single actuality of both alike… [Aristotle, as reproduced in Jaeger (2017), p. 7, our emphasis]

In quantum physics

Regarding the modal nature of quantum states in quantum physics:

In throwing dice we do not know the fine details of the motion of our hands which determine the fall of the dice and therefore we say that the probability for throwing a special number is just one in six. The probability wave of Bohr, Kramers, Slater, however, meant more than that; it meant a tendency for something. It was a quantitative version of the old concept of “potentia” in Aristotelian philosophy. It introduced something standing in the middle between the idea of an event and the actual event, a strange kind of physical reality just in the middle between possibility and reality. [Heisenberg (1958), our emphasis]


Aristotle‘s discussion of potentiality and actuality permeates his text Physics:

  • Aristotle, Physics, in: Jonathan Barnes (ed.), The Complete Works of Aristotle Vol 1 (1984) [pdf, ISBN:9780691016504]

  • Lorenzo Ferroni, Luca Gili, Non-existent but potentially actual. Aristotle on plenitude (Met. Θ 3-4, 1047b1-6), Revue de philologie, de littérature et d’histoire anciennes, Tome XC (2016) 81-114 [doi:10.3917/phil.901.0081]

See also:

With respect to quantum states in quantum physics:

further discussed in:

Last revised on August 4, 2023 at 14:35:06. See the history of this page for a list of all contributions to it.