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第6行： − − |first1=Friedel − − |first1=Friedel − − | first1 Friedel − − |last1=Weinert − − |last1=Weinert − − | last 1 Weinert − − |publisher=Springer − − |publisher=Springer − − 出版商：斯普林格 − − |year=2005 − − |year=2005 − − 出版时间：2005年 − − |isbn=978-3-540-21374-1 − − |isbn=978-3-540-21374-1 − − | isbn 978-3-540-21374-1 − − |page=143 − − |page=143 − − 共143页 − − |url=https://books.google.com/books?id=-R4ANHu-csMC}}, [https://books.google.com/books?id=-R4ANHu-csMC&pg=PA143 Chapter 4, p. 143]</ref> − − |url=https://books.google.com/books?id=-R4ANHu-csMC}}, [https://books.google.com/books?id=-R4ANHu-csMC&pg=PA143 Chapter 4, p. 143]</ref> − − |url=https://books.google.com/books?id=-r4anhu-csMC}}, [ https://books.google.com/books?id=-r4anhu-csmc&pg=pa143第4章，p. 143]</ref> − − − The symmetry of time ([[T-symmetry]]) can be understood simply as the following: if time were perfectly symmetrical, a video of real events would seem realistic whether played forwards or backwards.<ref>[http://www.isepp.org/Pages/01-02%20Pages/Albert.html David Albert on ''Time and Chance'']</ref> [[Gravity]], for example, is a time-reversible force. A ball that is tossed up, slows to a stop, and falls is a case where recordings would look equally realistic forwards and backwards. The system is T-symmetrical. However, the process of the ball bouncing and eventually coming to a stop is not time-reversible. While going forward, [[kinetic energy]] is dissipated and [[entropy]] is increased. Entropy may be one of the few processes that is [[Irreversibility|not time-reversible]]. According to the statistical notion of increasing entropy, the "arrow" of time is identified with a decrease of free energy.<ref>{{cite journal − − The symmetry of time (T-symmetry) can be understood simply as the following: if time were perfectly symmetrical, a video of real events would seem realistic whether played forwards or backwards. Gravity, for example, is a time-reversible force. A ball that is tossed up, slows to a stop, and falls is a case where recordings would look equally realistic forwards and backwards. The system is T-symmetrical. However, the process of the ball bouncing and eventually coming to a stop is not time-reversible. While going forward, kinetic energy is dissipated and entropy is increased. Entropy may be one of the few processes that is not time-reversible. According to the statistical notion of increasing entropy, the "arrow" of time is identified with a decrease of free energy.<ref>{{cite journal − − --[[用户:CecileLi|CecileLi]]([[用户讨论:CecileLi|讨论]]) 【审校】此段编辑视图中有中文翻译但阅读视图中无 第66行：
第17行： − 【文献：柏鲁（音译），柏鲁·T.K.，安尼利亚（音译）·A.《时间的道理》】+ 第77行：
第28行： − + − − == Eddington == − + − − 爱丁顿 − − In the 1928 book ''The Nature of the Physical World'', which helped to popularize the concept, Eddington stated: − − In the 1928 book The Nature of the Physical World, which helped to popularize the concept, Eddington stated: − − <blockquote>Let us draw an arrow arbitrarily. If as we follow the arrow we find more and more of the random element in the state of the world, then the arrow is pointing towards the future; if the random element decreases the arrow points towards the past. That is the only distinction known to [[physics]]. This follows at once if our fundamental contention is admitted that the introduction of randomness is the only thing which cannot be undone. I shall use the phrase 'time's arrow' to express this one-way property of time which has no analogue in space.</blockquote> − − <blockquote>Let us draw an arrow arbitrarily. If as we follow the arrow we find more and more of the random element in the state of the world, then the arrow is pointing towards the future; if the random element decreases the arrow points towards the past. That is the only distinction known to physics. This follows at once if our fundamental contention is admitted that the introduction of randomness is the only thing which cannot be undone. I shall use the phrase 'time's arrow' to express this one-way property of time which has no analogue in space.</blockquote> − − − − − − Eddington then gives three points to note about this arrow: − − Eddington then gives three points to note about this arrow: − − − − − − # It is vividly recognized by [[consciousness]]. − − It is vividly recognized by consciousness. − − # It is equally insisted on by our reasoning faculty, which tells us that a reversal of the arrow would render the external world nonsensical. − − It is equally insisted on by our reasoning faculty, which tells us that a reversal of the arrow would render the external world nonsensical. − − # It makes no appearance in physical science except in the study of organization of a number of individuals. (By which he means that it is only observed in entropy, a statistical mechanics phenomenon arising from a system.) − − It makes no appearance in physical science except in the study of organization of a number of individuals. (By which he means that it is only observed in entropy, a statistical mechanics phenomenon arising from a system.) − − − According to Eddington the arrow indicates the direction of progressive increase of the random element. Following a lengthy argument upon the nature of [[thermodynamics]] he concludes that, so far as physics is concerned, time's arrow is a property of [[entropy]] alone. − − According to Eddington the arrow indicates the direction of progressive increase of the random element. Following a lengthy argument upon the nature of thermodynamics he concludes that, so far as physics is concerned, time's arrow is a property of entropy alone. − + − − == Arrows == − − − − − − − − === Thermodynamic arrow of time === − − === Thermodynamic arrow of time === − − 热力学时间之箭 − − {{Main|Entropy (arrow of time)}} − − − − The arrow of time is the "one-way direction" or "asymmetry" of time. The thermodynamic arrow of time is provided by the [[second law of thermodynamics]], which says that in an isolated system, entropy tends to increase with time. Entropy can be thought of as a measure of microscopic disorder; thus the second law implies that time is asymmetrical with respect to the amount of order in an isolated system: as a system advances through time, it becomes more statistically disordered. This asymmetry can be used empirically to distinguish between future and past, though measuring entropy does not accurately measure time. Also, in an open system, entropy can decrease with time. − The arrow of time is the "one-way direction" or "asymmetry" of time. The thermodynamic arrow of time is provided by the second law of thermodynamics, which says that in an isolated system, entropy tends to increase with time. Entropy can be thought of as a measure of microscopic disorder; thus the second law implies that time is asymmetrical with respect to the amount of order in an isolated system: as a system advances through time, it becomes more statistically disordered. This asymmetry can be used empirically to distinguish between future and past, though measuring entropy does not accurately measure time. Also, in an open system, entropy can decrease with time.+ − + − − British physicist [[Brian Pippard|Sir Alfred Brian Pippard]] wrote, "There is thus no justification for the view, often glibly repeated, that the Second Law of Thermodynamics is only statistically true, in the sense that microscopic violations repeatedly occur, but never violations of any serious magnitude. On the contrary, no evidence has ever been presented that the Second Law breaks down under any circumstances."<ref>A. B. Pippard, Elements of Chemical Thermodynamics for Advanced Students of Physics (1966), p.100.</ref> However, there are a number of paradoxes regarding [[second law of thermodynamics#Irreversibility|violation of the second law of thermodynamics]], one of them due to the [[Poincaré recurrence theorem]]. − − British physicist Sir Alfred Brian Pippard wrote, "There is thus no justification for the view, often glibly repeated, that the Second Law of Thermodynamics is only statistically true, in the sense that microscopic violations repeatedly occur, but never violations of any serious magnitude. On the contrary, no evidence has ever been presented that the Second Law breaks down under any circumstances." However, there are a number of paradoxes regarding violation of the second law of thermodynamics, one of them due to the Poincaré recurrence theorem. − − 英国物理学家阿尔弗雷德·布莱恩·派帕德爵士写道: “经常油嘴滑舌地重复没有依据的观点是没有说服力的，尽管热力学第二定律理论只在统计学上是正确的，但是在微观世界中的相悖时常发生，且从未发生任何严重程度的相悖。相反，从来没有任何证据表明第二定律在任何情况下失效。”然而，一些违反热力学第二定律的悖论的确存在，其中一个是'''<font color="#ff8000">庞加莱始态复现定理the Poincaré recurrence theorem</font>'''。 − − − − − − This arrow of time seems to be related to all other arrows of time and arguably underlies some of them, with the exception of the [[#The particle physics (weak) arrow of time|weak arrow of time]].{{clarification needed|date=April 2019|reason=anchor lost results in unhelpful self reference, clarification of the weak arrow is needed}} − − This arrow of time seems to be related to all other arrows of time and arguably underlies some of them, with the exception of the weak arrow of time. − − − −
无编辑摘要
[书籍：The scientist as philosopher: philosophical consequences of great scientific discoveries《作为哲学家的科学家: 伟大科学发现的哲学影响》]
[书籍：The scientist as philosopher: philosophical consequences of great scientific discoveries《作为哲学家的科学家: 伟大科学发现的哲学影响》]
通常，人们认为，微观层面上的物理过程是全部或部分时间对称的。因此，即使时间的方向逆转，描述它们的理论仍然正确。然而，在宏观层面上，情况往往并非如此， 时间存在明显的方向(或流动)。
通常，人们认为，微观层面上的物理过程是全部或部分时间对称的。因此，即使时间的方向逆转，描述它们的理论仍然正确。然而，在宏观层面上，情况往往并非如此， 时间存在明显的方向(或流动)。
== 概览 ==
== 概览 ==
'''<font color="#ff8000"> 时间对称性The symmetry of time</font>'''可以简单地理解为: 如果时间是完全对称的，那么一段真实事件的视频，无论从前往后播放还是从后往前播放，都会显得很真实。例如，重力是一种时间可逆的力。一个球被抛起，然后下降、减速直至停止，在这种情况下正放和倒放看起来同样真实。该系统具有'''<font color="#ff8000"> 时间对称性The symmetry of time</font>'''。然而，球反弹并最终停止的过程是不可逆的。在前进过程中，动能耗散，熵增加。熵可能是少数几个处于时间不可逆的过程之一。根据熵增的统计概念，时间之箭被确定为自由能的减少。
'''<font color="#ff8000"> 时间对称性The symmetry of time</font>'''可以简单地理解为: 如果时间是完全对称的，那么一段真实事件的视频，无论从前往后播放还是从后往前播放，都会显得很真实。例如，重力是一种时间可逆的力。一个球被抛起，然后下降、减速直至停止，在这种情况下正放和倒放看起来同样真实。该系统具有'''<font color="#ff8000"> 时间对称性The symmetry of time</font>'''。然而，球反弹并最终停止的过程是不可逆的。在前进过程中，动能耗散，熵增加。熵可能是少数几个处于时间不可逆的过程之一。根据熵增的统计概念，时间之箭被确定为自由能的减少。
<ref>{{cite journal| author=Tuisku, P. |author2=Pernu, T.K. |author3=Annila, A. | title=In the light of time
<ref>{{cite journal| author=Tuisku, P. |author2=Pernu, T.K. |author3=Annila, A. | title=In the light of time
<ref>{{cite journal| author=Tuisku, P. |author2=Pernu, T.K. |author3=Annila, A. | title=In the light of time
<ref>{{cite journal| author=Tuisku, P. |author2=Pernu, T.K. |author3=Annila, A. | title=In the light of time
[文献：柏鲁（音译），柏鲁·T.K.，安尼利亚（音译）·A.《时间的道理》]
| journal=Proceedings of the Royal Society A | volume=465 |issue=2104 | pages=1173–1198 | year=2009
| journal=Proceedings of the Royal Society A | volume=465 |issue=2104 | pages=1173–1198 | year=2009
|doi=10.1098/rspa.2008.0494|bibcode = 2009RSPSA.465.1173T | doi-access=free }}</ref>
|doi=10.1098/rspa.2008.0494|bibcode = 2009RSPSA.465.1173T | doi-access=free }}</ref>
| doi 10.1098 / rspa. 2008.0494 | bibcode 2009RSPSA. 465.1173 t | doi-access free } / ref
| doi 10.1098 / rspa. 2008.0494 | bibcode 2009RSPSA. 465.1173 t | doi-access free } </ref>
== Eddington ==
== 爱丁顿 ==
在1928年出版的《物理世界的本质》一书中，爱丁顿推广了这个概念，他说:
在1928年出版的《物理世界的本质》一书中，爱丁顿推广了这个概念，他说:
“让我们任意画一个箭头。如果我们跟着箭头走，在这个世界中会发现越来越多随机元素，那么时间之箭就指向未来; 如果发现的随机元素越来越少，那么时间之箭就指向过去。这是物理学领域中我们对时间之箭已知的唯一区别。如果我们的这一基本论点得到承认，随机性的引入是唯一不可撤销的事情，那么这一点就立刻得到了证实。我会用“时间之箭”这个词来表达时间的这种单向性质，这种性质在空间上没有类似的东西”
“让我们任意画一个箭头。如果我们跟着箭头走，在这个世界中会发现越来越多随机元素，那么时间之箭就指向未来; 如果发现的随机元素越来越少，那么时间之箭就指向过去。这是物理学领域中我们对时间之箭已知的唯一区别。如果我们的这一基本论点得到承认，随机性的引入是唯一不可撤销的事情，那么这一点就立刻得到了证实。我会用“时间之箭”这个词来表达时间的这种单向性质，这种性质在空间上没有类似的东西”
关于这个箭头，爱丁顿指出了三个特点:
关于这个箭头，爱丁顿指出了三个特点:
意识能够生动地认识并理解它
意识能够生动地认识并理解它
我们的推理能力也同样可以证实这一点，它告诉我们，箭头的反转会使外部世界变得荒谬。
我们的推理能力也同样可以证实这一点，它告诉我们，箭头的反转会使外部世界变得荒谬。
除了在研究一些个体的组织结构外时，它在自然科学中没有出现。(他的意思是时间之箭只有在熵中才能观察到，而熵是一个系统产生的统计力学现象。）
除了在研究一些个体的组织结构外时，它在自然科学中没有出现。(他的意思是时间之箭只有在熵中才能观察到，而熵是一个系统产生的统计力学现象。）
根据爱丁顿的说法，箭头表示随机元素逐渐增加的方向。在对热力学性质进行了长时间的争论之后，他得出结论，就物理学而言，时间之箭是只属于熵的属性。
根据爱丁顿的说法，箭头表示随机元素逐渐增加的方向。在对热力学性质进行了长时间的争论之后，他得出结论，就物理学而言，时间之箭是只属于熵的属性。
== Arrows ==
== 箭头分类 ==
箭头分类
=== 热力学时间之箭 ===
时间之箭是指时间的“单向”或“不对称”。热力学的时间之箭是依据'''<font color="#ff8000"> 热力学第二定律the second law of thermodynamics'''，它在一个孤立的系统中，熵倾向于随着时间而增加。熵可以看作是一种对微观无序的度量; 因此，这就意味着在一个孤立的系统中，相对于有序的数量而言，时间是不对称的: 当一个系统随着时间推进时，它会变得更加无序。尽管测量熵并不能准确地测量时间，但这种不对称性可以用作区分未来和过去的经验。而且，在一个开放的系统中，熵会随着时间增加而减少。
时间之箭是指时间的“单向”或“不对称”。热力学的时间之箭是依据'''<font color="#ff8000"> 热力学第二定律the second law of thermodynamics'''，它在一个孤立的系统中，熵倾向于随着时间而增加。熵可以看作是一种对微观无序的度量; 因此，这就意味着在一个孤立的系统中，相对于有序的数量而言，时间是不对称的: 当一个系统随着时间推进时，它会变得更加无序。尽管测量熵并不能准确地测量时间，但这种不对称性可以用作区分未来和过去的经验。而且，在一个开放的系统中，熵会随着时间增加而减少。
英国物理学家阿尔弗雷德·布莱恩·派帕德爵士写道: “经常油嘴滑舌地重复没有依据的观点是没有说服力的，尽管热力学第二定律理论只在统计学上是正确的，但是在微观世界中的相悖时常发生，且从未发生任何严重程度的相悖。相反，从来没有任何证据表明第二定律在任何情况下失效。”<ref>A. B. Pippard, Elements of Chemical Thermodynamics for Advanced Students of Physics (1966), p.100.</ref> 然而，一些违反热力学第二定律的悖论的确存在，其中一个是'''<font color="#ff8000">庞加莱始态复现定理the Poincaré recurrence theorem</font>'''。
热力学时间之箭似乎与其它所有的时间之箭有关，并且可以说是除了弱时间之箭之外的一些之箭的基础。
热力学时间之箭似乎与其它所有的时间之箭有关，并且可以说是除了弱时间之箭之外的一些之箭的基础。
[[Harold F. Blum|Harold Blum]]'s 1951 book ''Time's Arrow and Evolution''<ref name="Blum1951">{{cite book|last=Blum|first=Harold F.|authorlink=Harold F. Blum|title=Time's Arrow and Evolution|url=https://books.google.com/books?id=tmcNnwEACAAJ|edition=First|year=1951|isbn=978-0-691-02354-0}}</ref> "explored the relationship between time's arrow (the second law of thermodynamics) and organic evolution." This influential text explores "irreversibility and direction in evolution and order, [[negentropy]], and [[evolution]]."<ref name=arrow-review>{{cite journal | doi = 10.1016/0019-1035(69)90059-1 | title= Book review: Time's arrow and evolution: Third Edition | journal = Icarus | volume = 11 | issue = 2 | pages = 278–279 | last = Morowitz | first = Harold J. | date = September 1969|bibcode = 1969Icar...11..278M | pmc = 2599115 }}</ref> Blum argues that evolution followed specific patterns predetermined by the inorganic nature of the earth and its thermodynamic processes.<ref name=yale>{{cite journal | pmc = 2599115 | title= Book reviews: Time's Arrow and Evolution | journal = [[Yale Journal of Biology and Medicine]] | volume = 24 | issue = 2 | pages = 164 | last = McN. | first = W. P. | date = November 1951}}</ref>
[[Harold F. Blum|Harold Blum]]'s 1951 book ''Time's Arrow and Evolution''<ref name="Blum1951">{{cite book|last=Blum|first=Harold F.|authorlink=Harold F. Blum|title=Time's Arrow and Evolution|url=https://books.google.com/books?id=tmcNnwEACAAJ|edition=First|year=1951|isbn=978-0-691-02354-0}}</ref> "explored the relationship between time's arrow (the second law of thermodynamics) and organic evolution." This influential text explores "irreversibility and direction in evolution and order, [[negentropy]], and [[evolution]]."<ref name=arrow-review>{{cite journal | doi = 10.1016/0019-1035(69)90059-1 | title= Book review: Time's arrow and evolution: Third Edition | journal = Icarus | volume = 11 | issue = 2 | pages = 278–279 | last = Morowitz | first = Harold J. | date = September 1969|bibcode = 1969Icar...11..278M | pmc = 2599115 }}</ref> Blum argues that evolution followed specific patterns predetermined by the inorganic nature of the earth and its thermodynamic processes.<ref name=yale>{{cite journal | pmc = 2599115 | title= Book reviews: Time's Arrow and Evolution | journal = [[Yale Journal of Biology and Medicine]] | volume = 24 | issue = 2 | pages = 164 | last = McN. | first = W. P. | date = November 1951}}</ref>