Editing Astrology (section)

=== Lack of mechanisms and consistency ===

Testing the validity of astrology can be difficult, because there is no consensus amongst astrologers as to what astrology is or what it can predict.<ref>{{cite book |last=Bennett |first=Jeffrey O. |title=The Cosmic Perspective |url=https://archive.org/details/astronomymediawo04lopr |url-access=registration |year=2007 |publisher=Pearson/Addison-Wesley |location=San Francisco |isbn=978-0-8053-9283-8 |pages=[https://archive.org/details/astronomymediawo04lopr/page/82 82–84] |edition=4th}}</ref> Most professional astrologers are paid to predict the future or describe a person's personality and life, but most horoscopes only make vague untestable statements that can apply to almost anyone.{{sfn|Bennett|2007}}<ref>{{cite book |last1=Eysenck |first1=H. J. |last2=Nias |first2=D. K. B. |title=Astrology: Science or Superstition? |year=1982 |publisher=St. Martin's Press |isbn=978-0-312-05806-7 |page=83}}</ref>

Many astrologers believe that astrology is scientific,<ref name="Chris-2012">{{cite news |last=Chris |first=French |title=Astrologers and other inhabitants of parallel universes |url=https://www.theguardian.com/science/2012/feb/07/astrologers-parallel-universes |work=The Guardian |date=7 February 2012 |access-date=8 July 2012 |location=London |archive-date=28 January 2019 |archive-url=https://web.archive.org/web/20190128233226/https://www.theguardian.com/science/2012/feb/07/astrologers-parallel-universes |url-status=live }}</ref> while some have proposed conventional [[Causality|causal agents]] such as [[electromagnetism]] and [[gravity]].<ref name="Chris-2012"/> Scientists reject these mechanisms as implausible<ref name="Chris-2012" /> since, for example, the magnetic field, when measured from Earth, of a large but distant planet such as Jupiter is far smaller than that produced by ordinary household appliances.<ref>{{cite book |editor-first=Michael |editor-last=Shermer |title=The Skeptic encyclopedia of pseudoscience |year=2002 |publisher=ABC-CLIO |location=Santa Barbara, Cal. |isbn=978-1-57607-653-8 |page=241}}</ref>

Western astrology has taken the earth's [[Precession#Axial precession (precession of the equinoxes)|axial precession (also called precession of the equinoxes)]] into account since Ptolemy's ''[[Almagest]]'', so the "first point of Aries", the start of the astrological year, continually moves against the background of the stars.<ref>{{cite book |last=Tester | first= S. J. | title=A History of Western Astrology | year=1987 | publisher=Boydell Press |isbn=978-0-85115-255-4 |page=161}}</ref> The tropical zodiac has no connection to the stars; tropical astrologers distinguish the constellations from their historically associated [[Astrological sign|sign]], thereby avoiding complications involving precession.<ref name="Charpak-2004" /> Charpak and Broch, noting this, referred to astrology based on the tropical zodiac as being "...empty boxes that have nothing to do with anything and are devoid of any consistency or correspondence with the stars."<ref name="Charpak-2004"/> Sole use of the tropical zodiac is inconsistent with references made, by the same astrologers, to the [[Age of Aquarius]], which depends on when the vernal point enters the constellation of Aquarius.{{sfn|Zarka|2011}}

Astrologers usually have only a small knowledge of astronomy, and often do not take into account basic principles—such as the precession of the equinoxes, which changes the position of the sun with time. They commented on the example of [[Élizabeth Teissier]], who wrote that, "The sun ends up in the same place in the sky on the same date each year", as the basis for the idea that two people with the same birthday, but a number of years apart, should be under the same planetary influence. Charpak and Broch noted that, "There is a difference of about twenty-two thousand miles between Earth's location on any specific date in two successive years", and that thus they should not be under the same influence according to astrology. Over a 40-year period there would be a difference greater than 780,000 miles.<ref name="Charpak-2004">{{cite book |last1=Charpak |first1=Georges |last2=Broch |first2=Henri |year=2004 |orig-date=2002 |title=Debunked!: ESP, Telekinesis, and Other Pseudoscience |url=https://books.google.com/books?id=DpnWcMzeh8oC&pg=PA6 |others=Translated by Bart K. Holland |location=Baltimore |publisher=The Johns Hopkins University Press |isbn=978-0-8018-7867-1 |at="Astrology in a Vacuum", pp. 6–7}}</ref>