Concept

Action at a distance

Overview

Action at a distance is the concept in physics that an object's motion can be affected by another object without the two being in physical contact; that is, it is the concept of the non-local interaction of objects that are separated in space. Coulomb's law and Newton's law of universal gravitation are based on action at a distance.

Historically, action at a distance was the earliest scientific model for gravity and electricity and it continues to be useful in many practical cases. In the 19th and 20th centuries, field models arose to explain these phenomena with more precision. The discovery of electrons and of special relativity led to new action at a distance models providing alternative to field theories. Under the modern understanding, the four fundamental interactions (gravity, electromagnetism, the strong interaction and the weak interaction) in all of physics are not described by action at a distance.

Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).

In the original texts

Passages from public-domain books where Action at a distance is discussed.

Either by trying to look upon contact forces as being themselves distant forces which admittedly are observable only at a very small distance--and this was the road which Newton's followers, who were entirely under the spell of his doctrine, mostly preferred to take; or by assuming that the Newtonian action at a distance is only _apparently_ immediate action at a distance, but in truth is conveyed by a medium…
Albert Einstein, Sidelights on Relativity
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And he had no need to consult the Devil, as men say he did, in order to learn that. Now the Philosopher of Stagira supposes that there are two kinds of Act, the permanent act and the successive act. The permanent or lasting act is nothing but the Substantial or Accidental Form: the substantial form (as for example the soul) is altogether permanent, at least according to my judgement, and the accidental is only so…
Gottfried Wilhelm Leibniz, Theodicy Essays on the Goodness of God, the Freedom of Man and the Origin of Evil
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This law of nature is called, in dynamics, the principle of the Composition of Forces: and in imitation of that well-chosen expression, I shall give the name of the Composition of Causes to the principle which is exemplified in all cases in which the joint effect of several causes is identical with the sum of their separate effects.
John Stuart Mill, A System of Logic
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After this examination we will find that nothing remains in the idea of body, except that it is something extended in length, breadth, and depth; and this something is comprised in our idea of space, not only of that which is full of body, but even of what is called void space.
René Descartes, Selections from the Principles of Philosophy
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This enables us to construct a string of events, each, approximately, growing out of a slightly earlier event according to an intrinsic law. Outside influences only affect the second order of small quantities. A string of events connected, in this way, by an approximate intrinsic law of development is called one piece of matter. This is what I mean by saying that the unity of a piece of matter is causal. I shall…
Bertrand Russell, Philosophy
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Related ideas

Place in the tradition

Part of Deductive-nomological model.

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