The term action-at-a-distance is often used to describe forces that travel through space and exert their effect without directly touching the objects acted upon.

 Newton's idea of instantaneous action-at-a-distance has been replaced by the modern action-at-a-distance which is transmitted at the speed of light so as to avoid conflict with Relativity Theory (Hoyle and Narlikar 1974).

The term "field theory" either replaces action-at-a-distance or is used as the means by which action-at-a-distance transmits force. In this paper "field" will represent the means of transmitting forces such as electromagnetism and gravity, avoiding the need for the term action-at-a-distance.