Present 873021 223329752 2008-07-03T16:25:47Z Lightbot 7178666 Units/dates/other {{otheruses}} The '''present''' is the [[time]] that is [[perception|perceived]] directly, not as a recollection or a speculation. It is often considered as a [[hyperplane]] in [[space-time]], often called ''now'', but it may also be viewed as a duration (see ''[[specious present]]''). When comparing time in places separated by great distances, the notion of ''present'' becomes unclear. For example, we visually perceive [[star]]s to be where they were when the [[light]] now reaching our eyes was emitted, because even though light travels at approximately [[speed of light|3 x 10<sup>8</sup> m/s]] it takes many years to reach us from distant sources. When used in the term "[[Before Present]]" (BP), as used in expressing ages or dates determined by [[radiocarbon dating]], "Present" is defined as AD 1950. Modern [[physics]] has not yet been able to explain what we normally understand by 'now'. Furthermore, there is no demonstrable reason why [[time]] should move in any one particular direction. This has led to the conclusion that the idea of a present is illusory and does not reflect the true nature of [[reality]]. The notion of "now" may be better understood as an unrealistic [[concept]] that has [[Evolution|evolved]] in humans and animals to give us an understanding of reality useful only to the extent necessary for survival. For example, if you say "now", the moment you say it, it is in the past. == The present according to Special Relativity == [[Image:World line2.svg|250px|right|thumb|A visualisation of the present (dark blue plane) and past and future [[light cone]]s in 2D space.]] It follows from [[Albert Einstein]]'s [[Special relativity|Special Theory of Relativity]] that there is [[Relativity of simultaneity|no such thing as absolute simultaneity]]. Therefore, if we define "present" to be the collection of events that are simultaneous with a given event, then "present" takes different meanings for different observers. Instead, with "present" defined as the events [[perception|perceived]] directly, not as a recollection or a speculation, for a given observer "present" takes the form of the observer's past [[light cone]]. The light cone of a given event is objectively defined as the collection of events in [[Causality (physics)|causal relationship]] to that event, but each event has a different associated light cone. One has to conclude that in relativistic models of physics there is no place for "the present" as an absolute element of reality. Einstein phrased this as: ''"People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion"''.<ref>Letter from Einstein to the family of his lifelong friend Michele Besso, after learning of his death, (March 1955) as quoted in ''Science and the Search for God'' ''Disturbing the Universe'' (1979) by [[Freeman Dyson]] Ch. 17 "A Distant Mirror" <!-- p 193 -->; also quoted at [http://speakingoffaith.publicradio.org/programs/einsteinsgod/unheardcuts.shtml ''Einstein's God'' (NPR)]</ref> == A philosophical problem == "The present" also raises another difficult question: "How is it that all sentient beings experience "now" at the same time?" There is no logical reason why this should be the case and no easy answer to the question. For example, say somebody named John is experiencing a great deal of pain. John's friend Fred takes pity on John because of John's situation. The problem is: is it logical for Fred to feel bad for John at present, when there is no way to prove that both John and Fred experience the same [[temporal parts|temporal existence]]? (See also [[Solipsism]] and [[Philosophy of mind]].) == The present in Buddhism == [[Buddhism]] and many of its associated [[philosophy|philosophies]] emphasize the importance of living in the present moment &mdash; being fully aware of what is happening, and not dwelling on the [[past]] or worrying about the [[future]]. This does not mean that they encourage [[hedonism]], but merely that through constantly focusing on one's current position in space and time (rather than future considerations, or past reminiscence) will aid one in relieving suffering. A number of [[meditation|meditative]] techniques aim to help the practicer live in the present moment. == Christianity and eternity == [[God]] is viewed as being outside of time and from the divine perspective past, present and future are actualised in the now of [[eternity]]. [[Saint Thomas Aquinas]] used the image of a watchman, representing God, standing on a height looking down on a valley where past present and future, represented by the individuals and their actions strung out along its length, are all visible simultaneously to God. == Eternal now == [[Eckhart Tolle]], in his book ''[[The Power of Now]]'' (1997), argues that only the present moment exists. Tolle argues that time is an illusion, and that the past exists only as a memory stored in the mind, while the future is imagined, a projection of the mind.<ref>[[Eckhart Tolle|Tolle, Eckhart]] (1999). ''[[The Power of Now: A Guide to Spiritual Enlightenment]]''. New World Library. pp 36-37. ISBN 978-1577311522</ref> ==Quotes== {{quotation|There's no present. There's only the immediate future and the recent past.|George Carlin}} {{quotation|You shouldn't chase after the past or place expectations on the future. What is past is left behind. The future is as yet unreached. Whatever quality is present you clearly see right there, right there.|[[Gautama Buddha|Buddha]]|Bhaddekaratta Sutta<ref name="Buddha">[http://www.accesstoinsight.org/tipitaka/mn/mn.131.than.html MN 131: Bhaddekaratta Sutta<!-- Bot generated title -->]</ref>}} {{quotation|What we perceive as present is the vivid fringe of memory tinged with anticipation.|[[Alfred North Whitehead]]|The Concept of Nature<ref name="Alfred North Whitehead">Whitehead, Alfred North. ''The Concept of Nature'' (Cambridge: Cambridge University Press, 1930), p. 73</ref>}} {{quotation|There's no time like the present.|Common saying}} ==See also== * [[Arrow of time]] * [[Here]] ==References== {{reflist}} * Greene, Brian, (2004). ''The Fabric of the Cosmos: Space, Time, and the Texture of Reality.'' Knopf. ISBN 0-375-41288-3 * Stepath, Katrin, (2006). ''Gegenwartskonzepte.'', Würzburg. ISBN 3-8260-3292-6 ==External links== * [http://plato.stanford.edu/archives/win2004/entries/time-experience/ The Experience and Perception of Time] {{Time Topics}} [[Category:Philosophy of time]] [[Category:Time]] [[af:Hede]] [[als:Gegenwart]] [[cs:Přítomnost]] [[da:Nutiden]] [[de:Gegenwart]] [[et:Olevik]] [[es:Presente (tiempo)]] [[eu:Orain]] [[fr:Aujourd'hui]] [[ko:현재]] [[it:Oggi]] [[he:הווה]] [[nl:Heden]] [[ja:現在]] [[no:I dag]] [[pt:Hoje (dia)]] [[qu:Kunan pacha]] [[ru:Настоящее]] [[sk:Prítomnosť]] [[sl:Sedanjost]] [[fi:Nykyhetki]] [[sv:Nutid]] [[yi:היינט]] [[zh-yue:今日]] [[zh:今天]]