Non-deterministic

Definition:
Non-deterministic refers to a process or system whose outcomes are inherently unpredictable and cannot be exactly repeated, even when starting from the same initial conditions. It contrasts with deterministic systems, where the same inputs always produce the same outputs.

Scientific context:
In quantum mechanics, many phenomena are fundamentally non-deterministic. For example, the outcome of measuring a quantum state—such as the spin of an electron or the polarization of a photon—is not determined in advance, but rather follows a probabilistic distribution governed by the wavefunction.

Non-determinism is also relevant in quantum random number generation, where quantum measurements yield truly random outcomes, unlike pseudo-random processes in classical systems. In quantum communication and computation, non-deterministic behaviour often reflects the probabilistic nature of quantum state collapse upon measurement.

Did you know?
The non-deterministic nature of quantum mechanics was one of the key reasons Einstein criticized the theory, famously saying, “God does not play dice.”