Concept
Uncertainty principle
Overview
The uncertainty principle, also known as Heisenberg's indeterminacy principle, is a fundamental concept in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position and momentum, can be simultaneously known. In other words, the more accurately one property is measured, the less accurately the other property can be known.
More formally, the uncertainty principle is any of a variety of mathematical inequalities asserting a fundamental limit to the product of the accuracy of certain related pairs of measurements on a quantum system, such as position, x, and momentum, p. Such paired-variables are known as complementary variables or canonically conjugate variables.
First introduced in 1927 by German physicist Werner Heisenberg, the formal inequality relating the standard deviation of position σx and the standard deviation of momentum σp was derived by Earle Hesse Kennard later that year and by Hermann Weyl in 1928:
where
ℏ
=
h
2
π
{\displaystyle \hbar ={\frac {h}{2\pi }}}
is the reduced Planck constant.
The quintessentially quantum mechanical uncertainty principle comes in many forms other than position–momentum. The energy–time relationship is widely used to relate quantum state lifetime to measured energy widths but its formal derivation is fraught with confusing issues about the nature of time. The basic principle has been extended in numerous directions; it must be considered in many kinds of fundamental physical measurements.
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
Possible passages
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The comparison of time-measurements in diverse time-systems requires two other axioms. The first of these axioms, forming the fifth axiom of congruence, will be called the axiom of 'kinetic symmetry.' It expresses the symmetry of the quantitative relations between two time-systems when the times and lengths in the two systems are measured in congruent units. The axiom can be explained as follows: Let {alpha} and…
Alfred North Whitehead, The Concept of Nature The Tarner Lectures Delivered in Trinity College, November 1919
States what Uncertainty principle is.
It may be observed that the introduction of "local time" suggested by the principle of relativity has effected, for purely scientific reasons, much the same multiplication of times as we have just been advocating. The sum-total of all the particulars that are (directly) either simultaneous with or before or after a given particular may be defined as the "biography" to which that particular belongs.
Bertrand Russell, Mysticism and Logic and Other Essays
States what Uncertainty principle is.
So that when the scale is moved over the line by any continuous series of shiftings of one kind, there are two points which no numbers on the scale can ever reach, except the numbers fixed there. This pair of points, thus unattainable in measurement, is called the Absolute. These two points may be distinct and real, or they may coincide, or they may be both imaginary.
Charles S. Peirce, Chance, Love, and Logic
States what Uncertainty principle is.
Philosophers who discussed Uncertainty principle
Related ideas
- Falsifiability
- Princeton University Press
- Philosophical realism
- Carl Friedrich von Weizsäcker
- Second law of thermodynamics
- The Logic of Scientific Discovery
- Karl Popper
- Quantum decoherence
- David Bohm
- Momentum
- Niels Bohr
- Reductio ad absurdum
- Physics
- Particle physics
- Photon
- Quantum mechanics
- Quantum field theory
- Quantum entanglement
- Werner Heisenberg
- Wave
- Accuracy and precision
- Mass–energy equivalence
- Born rule
- Probability density function
Opposing perspectives
Place in the tradition
Part of Deductive-nomological model.