(quantum mechanics) The Heisenberg uncertainty principle.

(quantum mechanics) The Heisenberg uncertainty principle.

a peculiar principle once erroneously supposed to form the basis of all vegetable extracts

(physics) The assumption that each point on a wavefront may be regarded as a source of secondary waves and that the position of the wavefront at a later time is determined by the envelope of these secondary waves; proposed in order to explain the fact that light travels in a straight line and casts sharp shadows.

The notion that more will be given to those that already have.

The principle that describes the phenomenon wherein a small percentage of a population accounts for a large proportion of a particular characteristic of that population.

Any scientific principle that expresses various reciprocal relationships for the behaviour of a physical system.

Any of the six recommendations that arose from an investigation of decommissioning of weapons in Northern Ireland in 1996, urging all parties involved in the conflict to renounce violence and agree to disarmament before entering into all-party negotiations.

(management) The theory that people in an organization tend to rise (be promoted) to the level of their incompetence.

Any of several similar explanations for the nature of the universe, and for the values of its fundamental constants, that states either that the universe is as it is because otherwise we wouldn't be here to observe it, or that the very presence of intelligent life constrains the universe to be as it is.