Changes

'''Relativity''' is a mathematical system built on untestable hypotheses.  By relying on ''assumptions'' about nature rather than ''observations'', the theories of relativity violate [[Isaac Newton]]'s rule against the use of hypotheses:  "Hypotheses non fingo" ("I feign no hypotheses)".<ref>http://plato.stanford.edu/entries/newton-philosophy/</ref>  Relativity also rejects -- without any experimental evidence -- Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]].

'''Relativity''' is a mathematical system built on untestable hypotheses.  By relying on ''assumptions'' about nature rather than ''observations'', the theories of relativity violate [[Isaac Newton]]'s rule against the use of hypotheses:  "Hypotheses non fingo" ("I feign no hypotheses)".<ref>http://plato.stanford.edu/entries/newton-philosophy/</ref>  Relativity also rejects -- without any experimental evidence -- Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]].

The [[non-locality]] of [[quantum mechanics]] and [[Newton]]ian physics contradicts the theories of relativity, which assume that time is an intrinsic part of space and assumes absolute locality. Causality breaks down under relativity if information can be transmitted faster than the speed of light. In addition, the [[uncertainty principle]] suggests that light [[photons]] must sometimes travel faster than the speed of light despite the assumption of relativity; "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref>  Quantum field theory is another attempt to partially reconcile relativity with quantum mechanics.  But "quantum field theory, which was born just fifty years ago from the marriage of quantum mechanics with relativity, is a beautiful but not very robust child."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1979/weinberg-lecture.pdf (p. 556)</ref>

Unlike [[Newton]]ian physics, in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x² - c t²). The (assumed) instantaneous transmission of [[Newton]]ian gravitational effects also contradicts special relativity.

 

In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref>  Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics.  [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity.

== Special Relativity ==

== Special Relativity ==