答《評阮曉鋼教授的“觀測相對論”》

阮曉鋼

(北京工業(yè)大學(xué)信息學(xué)部，北京 100124)

愛因斯坦相對論揭示了物質(zhì)運動的相對論性現(xiàn)象，自建立以來，得到幾乎所有觀測和實驗支持，令我們知其然. 然而，直到今天，我們的物理學(xué)依然不能解釋光速為什么不變，物質(zhì)運動為什么會呈現(xiàn)相對論性現(xiàn)象，令我們不知其所以然. 愛因斯坦相對論，包括狹義的和廣義的，都已經(jīng)建立100多年. 畢竟，人類的物理學(xué)還得繼續(xù)：對于物質(zhì)運動的相對論性現(xiàn)象，我們不能永遠停滯在這種只知其然而不知其所以然的境地.

2020年伊始，《北京工業(yè)大學(xué)學(xué)報》刊載了作者的《觀測與相對論：光速在愛因斯坦狹義相對論中為什么不變？》[1](以下簡稱《觀測與相對論》)，報道了一項新的理論：觀測相對論(observational relativity，OR). OR從理論上證明，觀測媒介的速度具有觀測上的不變性，而光速不變性只是其中的個例：光速不變性是光或電磁相互作用擔(dān)當(dāng)觀測媒介時的情形. 根據(jù)OR理論，物理學(xué)所有理論均源于觀測，不同觀測體系導(dǎo)致不同理論體系：伽利略變換和牛頓定律是理想觀測體系的產(chǎn)物；而洛倫茲變換和愛因斯坦相對論則是光學(xué)觀測體系的產(chǎn)物. OR理論表明，所有相對論性現(xiàn)象，包括光速不變性，皆觀測效應(yīng)，乃觀測局域性所致，而非客觀真實的自然現(xiàn)象.

OR理論，令我們對于物質(zhì)運動的相對論性現(xiàn)象，不僅知其然，而且，知其所以然！

然而，正如作者所預(yù)料的，自2019年9月10日中國知網(wǎng)首發(fā)《觀測與相對論》以來，還未正式見刊，不少讀者，其中包括造詣深厚的物理學(xué)家，便給予了評述和質(zhì)疑. 有國內(nèi)位居中國科學(xué)院院士的權(quán)威物理學(xué)家一言以蔽之：“把相對論歸結(jié)為觀測效應(yīng)完全是錯誤的！”

首先，作者真誠地感謝評述和質(zhì)疑OR理論的讀者. 無論如何，OR理論能得到大家的批判和關(guān)注，既是OR的榮幸，也是作者的榮幸.

美國田納西大學(xué)教授王令雋先生，是第一位正式致函《北京工業(yè)大學(xué)學(xué)報》評述和質(zhì)疑OR理論的物理學(xué)家. 王令雋先生在理論物理學(xué)界頗有造詣和學(xué)術(shù)影響；他對OR理論的評論和質(zhì)疑富于教義，值得我們思考. 以下便是作者對王令雋先生之《評阮曉鋼教授的“觀測相對論”》的答復(fù)，同時，稍做引申，一并回復(fù)其他類同的評論或質(zhì)疑.

1 OR理論不是制造出來的

王令雋評：“我非常贊賞阮教授和評論員敢于挑戰(zhàn)權(quán)威，敢于批判相對論的精神. ……. 只有物理學(xué)界重新樹立了文藝復(fù)興時期建立起來的科學(xué)批判精神，才能客觀地梳理20世紀理論物理學(xué)的諸多問題，走出困境. ……. ”

阮曉鋼答：謝謝王令雋先生的鼓勵.

需要特別說明：OR理論與“體制”無關(guān)，所涉及的是純粹的學(xué)術(shù)問題；國內(nèi)外主流物理學(xué)界對于愛因斯坦相對論所持的認知和態(tài)度并無二致.

《觀測與相對論》的初衷和OR的結(jié)論都并非是對愛因斯坦相對論的“批判”. 科學(xué)的目的不是“批判”. 科學(xué)不能以“批判”為其出發(fā)點，更不能為了“批判”而“批判”.

毫無疑問，愛因斯坦相對論是人類物理學(xué)史上最為偉大的成就之一. OR理論與愛因斯坦相對論是相容的. 實際上，OR理論是對愛因斯坦相對論的繼承和發(fā)展.

然而，正如Hawking[2]在其《時間簡史》中所言：“物理學(xué)任何理論都是暫時的，從某種意義上說，它只是一個假設(shè)：你永遠無法證明它. 不管實驗結(jié)果與理論一致多少次，你永遠無法確定下一次的結(jié)果是否會與理論相悖. ”O(jiān)R向我們闡明：愛因斯坦相對論只是一個“局部理論”(如霍金所說的Partial Theory)，僅當(dāng)我們的觀測體系以光或電磁相互作用為觀測媒介時成立.

需要特別指出：OR理論不是“制造”出來的，更不是為了反對或批判愛因斯坦相對論而“設(shè)計”的；它只是個“發(fā)現(xiàn)”，是邏輯和理論的產(chǎn)物.

OR只是不經(jīng)意間的一個“發(fā)現(xiàn)”.

2 一切相對論性效應(yīng)皆觀測效應(yīng)

王令雋評：“把相對論的結(jié)論歸結(jié)于‘觀察效應(yīng)’，是掩蓋或抹煞相對論的本質(zhì). ……. 難道廣島長崎的毀滅僅僅是‘觀測效應(yīng)’而不是物理真實？難到觀測一下就可以創(chuàng)造出宇宙？……. ‘相對論觀測效應(yīng)’論歷史上早已有之，阮教授并不是首倡者. ……. 這樣的‘批判’不僅不能解釋相對論的謬誤，反而可能誤入相對論的巢臼而犯同樣的錯誤. ……. ”

“總而言之，相對論的理論及其結(jié)論是完全不同于經(jīng)典物理的革命性理論，不能僅僅歸結(jié)為觀測效應(yīng). ”

阮曉鋼答：王令雋先生質(zhì)疑OR“一切相對論性效應(yīng)皆觀測效應(yīng)”之說，其表達的觀點與前面提到的權(quán)威物理學(xué)家的觀點相同.

OR理論建立起來之前，作者并無任何關(guān)于“一切相對論性效應(yīng)皆觀測效應(yīng)”的思想或觀念. “一切相對論性效應(yīng)皆觀測效應(yīng)”是OR的“發(fā)現(xiàn)”，是OR的邏輯結(jié)論，是理論推導(dǎo)的結(jié)果，并非作者的主觀認知或個人主張.

OR是物質(zhì)運動的理論模型，既是基于思辨的，也是基于實證的. 質(zhì)疑或批判物理學(xué)理論模型，有2條正確的途徑：要么，通過思辨，舉證其邏輯演繹和理論推導(dǎo)中存在的錯誤，否定其邏輯上的有效性或理論上的正確性；要么，通過實證，用觀測和實驗證偽之. 我們不能僅僅基于主觀認知或個人主張批判OR理論.

的確，如王令雋先生所言：“‘相對論觀測效應(yīng)’論歷史上早已有之，阮教授并不是首倡者. ”然而，那只是些基于主觀認知的個人主張而已，并非邏輯和理論的產(chǎn)物，并未形成任何可與OR比擬的理論體系或物理模型. 不過，有一點值得思考：這些人(其中不乏資深物理學(xué)家)如此主張之時，似乎并不擔(dān)心其主張可能引發(fā)“觀測可以創(chuàng)造宇宙”或“原子彈爆炸乃觀測效應(yīng)”這樣的悖論.

的確，許多物理人認為，原子彈爆炸所釋放出的巨大能量可用愛因斯坦質(zhì)能公式E=mc2解釋：質(zhì)量可以變換為能量，而且，是巨大的能量. 甚至有報道稱，科學(xué)家的確發(fā)現(xiàn)原子彈爆炸后，物質(zhì)質(zhì)量減少了！(我們很難想象，科學(xué)家們怎么能測定原子彈爆炸前后的物質(zhì)質(zhì)量. )

實際上，愛因斯坦的質(zhì)能公式只是其狹義相對論中的一個關(guān)系式，與原子核物理無關(guān)！原子能，又稱核能，是原子核內(nèi)固有的能量，與強相互作用相關(guān)，與愛因斯坦相對論無關(guān). 原子彈爆炸瞬間產(chǎn)生的巨大能量源于無數(shù)原子之固有能量連鎖反應(yīng)式的釋放，與物質(zhì)質(zhì)量無關(guān). 維基百科條目《質(zhì)能等價》[3]有這樣一段話：“有人認為這一公式直接導(dǎo)致了原子彈的設(shè)計和制造，但事實上質(zhì)能轉(zhuǎn)換公式對于原子理論和原子彈的設(shè)計和制造并無任何的直接或間接促進作用，而僅僅是后人用來解釋原子彈原理的解釋工具之一. ”Isaackson[4]在《連鎖反應(yīng)：從愛因斯坦到原子彈》中也說：“與一般的認識相反，愛因斯坦對作為原子彈基礎(chǔ)的核物理知之甚少.”用愛因斯坦寫給勞厄信中的話說[5]：“關(guān)于原子彈和羅斯福，我所做的僅僅是：鑒于希特勒可能首先擁有原子彈的危險，我簽署了一封由西拉德起草給總統(tǒng)的信. ”

在愛因斯坦相對論中，相對論性被視為物質(zhì)運動的固有特性，被視為客觀真實的物理存在. 這成為主流物理學(xué)界的觀點和認識，因為，愛因斯坦相對論，包括狹義的和廣義的，經(jīng)歷了一個多世紀的時間檢驗，得到幾乎所有觀測和實驗支持. 然而，正如美國《科學(xué)》雜志(Science)評論員Adrian Cho[6]在其紀念愛因斯坦狹義相對論誕生100周年之際撰文所感嘆的：“那么為什么還有那么些人試圖證明它是錯誤的呢？”

如此成功的狹義相對論依然遭受質(zhì)疑，其根本原因在于，人們不能理解光速為什么不變，物質(zhì)運動為什么會呈現(xiàn)相對論性效應(yīng).

人們對于光速不變性的認識始于邁克爾遜- 莫雷實驗，其本身是一種相對論性效應(yīng).

特別注意：光速不變性是愛因斯坦相對論的邏輯前提；因此，愛因斯坦相對論本身并不能解釋光速為什么不變，也不能解釋物質(zhì)運動為什么會呈現(xiàn)相對論性效應(yīng).

OR理論發(fā)現(xiàn)了物質(zhì)運動之相對論性的本質(zhì)和根源：物理學(xué)之一切理論皆依賴于并制約于觀測；物質(zhì)運動之一切相對論性效應(yīng)皆觀測效應(yīng). 這便是“觀測相對論”中“觀測”的含義.

從某種意義上說，“一切相對論性效應(yīng)皆觀測效應(yīng)”是OR理論最重要的發(fā)現(xiàn)！

OR從理論上導(dǎo)出了觀測媒介速度不變性，揭示了光速在邁克爾遜- 莫雷實驗中不變的根源：光在邁克爾遜- 莫雷實驗中扮演著觀測媒介的角色；所謂光速不變性原理，僅當(dāng)光或電磁相互作用作為觀測媒介時才能成立.

OR理論告訴我們：真實的物理世界，并非馬赫和愛因斯坦為我們描繪的相對時空，而是伽利略和牛頓為我們描繪的絕對時空.

值得注意，OR理論體系中的廣義洛倫茲變換概括統(tǒng)一了伽利略變換和洛倫茲變換，并且，在玻爾對應(yīng)原理[7](The Correspondence Principle)下，與伽利略變換和洛倫茲變換嚴格對應(yīng)：η=c時，OR之廣義洛倫茲變換蛻化為洛倫茲變換；η=∞時，OR之廣義洛倫茲變換蛻化為伽利略變換. 這種嚴格對應(yīng)關(guān)系從一個側(cè)面印證了廣義洛倫茲變換變換以及OR理論邏輯上的合理性和理論上的正確性.

科學(xué)的使命在于探索未知，其中，最根本的，在于探明自然現(xiàn)象所蘊含的本質(zhì)，即“所以然”. 現(xiàn)在，對于物質(zhì)運動的相對論性，OR不僅令我們知其然，而且令我們知其所以然. 基于OR理論，我們終于明白：光在愛因斯坦相對論中擔(dān)當(dāng)著觀測媒介的角色；一切相對論性效應(yīng)，包括光速不變性、同時性的相對性、時漲尺縮效應(yīng)，甚至，時空彎曲效應(yīng)和量子效應(yīng)，皆觀測效應(yīng)！

3 關(guān)于狹義相對論的邏輯前提

王令雋評：“阮教授說：‘正是基于光速不變性假設(shè)，愛因斯坦成功地從理論上推導(dǎo)出洛倫茲變換，建立狹義相對論，揭示了時空和物質(zhì)運動的相對性現(xiàn)象. 光速不變性假設(shè)不僅是愛因斯坦SR的基石，同時，也是愛因斯坦廣義相對論的前提之一. ’這段議論言過其實. ”

“首先，僅僅基于光速不變性假設(shè)，是不能推導(dǎo)出洛倫茲變換的……. ”

阮曉鋼答：王令雋先生說，除光速不變性假設(shè)之外，愛因斯坦狹義相對論還有其他假設(shè)，比如，要求時空變換關(guān)系是線性的；意在批評作者的對于愛因斯坦狹義相對論的無知，盡管這似乎與OR理論是否成立無關(guān).

眾所周知，愛因斯坦狹義相對論之邏輯前提有兩大原理：第一，光速不變性原理；第二，相對性原理. 其實，還有鮮為人知的第三大原理：簡單性原理[8](The Principle of Simplicity).

王令雋先生提到的線性時空變換關(guān)系應(yīng)歸結(jié)為簡單性原理；依愛因斯坦自己的說法[9]，其線性時空變換歸結(jié)于時空的均勻性. 如果王令雋先生細心閱讀《觀測與相對論》，便知其中有關(guān)于線性時空變換的內(nèi)容. 關(guān)于簡單性原理和線性時空變換，作者在文獻[10-11]中有更為詳盡的論述. 王令雋先生若有興趣，不妨一讀.

順便指出，文獻[10-11]給出了OR原本的和完整的邏輯演繹過程，其中，OR由更基本的邏輯前提出發(fā)，并未借用簡單性原理或假設(shè)時空變換是線性的，也未借用相對性原理，卻直接地導(dǎo)出了微分形式(而非代數(shù)形式)的洛倫茲變換. (這涉及王令雋先生關(guān)于OR邏輯與愛因斯坦邏輯的關(guān)系問題，待作者稍后答復(fù). )

4 光速不變性假設(shè)與廣義相對論

王令雋評：“其次，光速不變原理并不是廣義相對論的前提之一，和愛因斯坦引力場方程的建立了無關(guān)系. 事實上，廣義相對論和光速不變原理直接相悖. 這非常容易證明. ……. ”

阮曉鋼答：王令雋先生意在批評作者對于愛因斯坦廣義相對論的無知，盡管這似乎也與OR是否成立無關(guān).

王令雋先生給出了一個基于Schwarzschild度規(guī)[12]的引力場光速公式：v=dr/dt=±(1-rs/r)c，以說明光速在引力場中是變化的，進而證明：光速不變性并非廣義相對論的邏輯前提.

根據(jù)廣義相對論，引力場中的光速的確是位置的函數(shù)；這無須引用Schwarzschild度規(guī). 然而，這并不排斥光速不變性乃廣義相對論之邏輯前提. 或許，王令雋先生沒太留意，《觀測與相對論》中有關(guān)于Schwarzschild度規(guī)與時空彎曲的內(nèi)容. 根據(jù)OR理論，“時空彎曲”其實也只是一種源于光之觀測局域性的觀測效應(yīng).

有一種說法：真正懂得廣義相對論的人，世界上只有2個(也有說3個的). 有人問愛丁頓：“據(jù)說，世界上只有3個人真正懂得愛因斯坦廣義相對論，是真的嗎？”愛丁頓立刻追問道：“那第3個人是誰呢？”愛丁頓言下之意，真正懂得愛因斯坦廣義相對論的就2個人：一個是創(chuàng)立廣義相對論的愛因斯坦自己；而另一個則是他自己. 這類故事的真實性無從考證，然而，似乎確有其合理性.

愛因斯坦廣義相對論建立100多年了. 然而，人們，包括資深物理學(xué)家，以及那些專門研究廣義相對論或為廣義相對論著書立說的物理學(xué)家，仍然對其持有許多模糊不清的認識. 就光速不變性是否為廣義相對論邏輯前提這一問題，相關(guān)的論述便模糊不清，甚至自相矛盾.

根據(jù)文獻[13]記載，愛因斯坦曾說：“光速在引力場中是位置的函數(shù)；真空中的光速不變性原理必須加以修正. ……. 光速不變性原理仍然適用于這個理論，但它已不像平常那樣作為通常的相對論基礎(chǔ)來理解了. ”(看來，對于光速不變性假設(shè)是否為廣義相對論的邏輯前提，愛因斯坦自己也有些含糊.)據(jù)此，劉明成和劉文芳[14]認為有必要進一步闡明光速不變性是否為愛因斯坦廣義相對論的邏輯前提. 他們的結(jié)論是：“光速不變原理仍然適用于廣義相對論. 但它已不像平常那樣作為通常的相對論的基礎(chǔ)來理解了. 引力場中坐標時光速是位置的函數(shù)，它不能直接被測量. 真空中光速不變原理經(jīng)過修改而更為明確：光速的固有值，即局部慣性系的測量值，不變. ”這像是在重復(fù)愛因斯坦的話；無論如何，其中有一點值得肯定：“光速在局部慣性系中的測量值不變. ”

趙崢[15]在《廣義相對論入門講座》中寫到：“愛因斯坦想，既然慣性系無法定義，不如取消它在相對論中的特殊地位，把自己的整個理論置于‘任意參考系’的框架中，即假定相對性原理和光速不變原理在任何參考系中都成立，而不僅僅只在慣性系中成立. 這樣，狹義相對性原理被推廣為廣義相對性原理. 光速不變原理適用的范圍也從慣性觀測者推廣到任意觀測者：‘任意觀測者測量的光速都是c.’”我不敢相信愛因斯坦對光速不變性原理做過如此推廣. 王令雋先生質(zhì)疑 “光速不變性也是廣義相對論邏輯前提之一”的論據(jù)，似乎更適合用來質(zhì)疑趙崢在文獻[15]中的論述.

劉遼和趙崢[16]在其撰寫的教材中說：“在廣義相對論中，實驗測得的物理量都是用標準鐘和標準尺測得的固有量，而非坐標量. 在靜態(tài)引力場中，用標準鐘和標準尺測得真空中的光速與狹義相對論一樣，恒等于c. ”其言下之意，光速不變性原理在靜態(tài)引力場中似乎是成立的.

那么，光速不變性假設(shè)，到底是不是愛因斯坦廣義相對論的邏輯前提呢？

答案是肯定的！

光速c為什么會出現(xiàn)在廣義相對論和愛因斯坦場方程中？OR理論告訴我們，這是因為：與愛因斯坦狹義相對論中的情形一樣，光在愛因斯坦廣義相對論中扮演著觀測媒介的角色！

愛因斯坦廣義相對論最令人津津樂道的邏輯前提是等效原理(The Equivalence Principle). 所謂等效原理，簡而言之，指時空之引力場與慣性力場的物理效應(yīng)是局域不可分辨的. 然而，人們(包括許多物理學(xué)家)卻并不十分清楚等效原理在愛因斯坦廣義相對論中究竟怎么發(fā)揮作用.

特別需要指出，在愛因斯坦廣義相對論中，等效原理需要借助光速不變性假設(shè)方能發(fā)揮作用！事實上，沒有光速不變性假設(shè)，光速c就不可能進入愛因斯坦廣義相對論，當(dāng)然，也就不可能進入愛因斯坦場方程.

在光學(xué)觀測體系中，限于光之觀測局域性，引力時空看上去是“彎曲”的，而“彎曲”時空的幾何特性需要微分幾何作為其形式化工具：其中，“彎曲”的時空可由“微小”的慣性時空局部地逼近. 于是，基于等效原理，愛因斯坦方能將“彎曲”的引力時空局部地“等效”為“平直”的慣性時空，其中，光速不變性原理成立，光因而能以不變的速度c在局部慣性中傳遞信息. 這令我們想起了文獻[14]曾經(jīng)的結(jié)論：“光速在局部慣性系中的測量值不變. ” 由此，光速c便獲準進入了愛因斯坦廣義相對論及其場方程.

可見，光速不變性假設(shè)不僅是愛因斯坦狹義相對論的邏輯前提，而且，也是愛因斯坦廣義相對論重要的和不可或缺的邏輯前提！

5 觀測媒介的地位和作用

王令雋評：“愛因斯坦把光置于一個特別的絕對的位置. 光就是電磁波……對于時空結(jié)構(gòu)沒有也不應(yīng)該有決定理論架構(gòu)的作用. 可是，在愛因斯坦的相對論中，光卻被賦予了決定時空結(jié)構(gòu)的永久性的特殊位置. ……其荒謬是顯而易見的. ”

“物理量的測量必須通過媒介嗎？當(dāng)我們用米尺測量桌子的長度時，我們直接比較桌子與米尺的刻度. 當(dāng)我們數(shù)著白天黑夜測量時間的流逝時，我們用的是地球自傳的穩(wěn)定周期. 當(dāng)我們……. 在所有這些測量中，都不需要媒介. ”

“阮教授……中了相對論教義維護者的圈套. ”

阮曉鋼答：王令雋先生既反對愛因斯坦在狹義相對論中給予光或光速特殊的地位，同時，又反對OR理論的“觀測媒介”說.

像許多的物理人一樣，王令雋先生的困惑在于：一方面，主觀地認為，愛因斯坦相對論賦予光或光速特殊地位是“荒謬”的；另一方面，又苦于無從知曉光在愛因斯坦相對論中扮演什么角色，光速在洛倫茲變換中的物理意義是什么，光速為什么會不變. 現(xiàn)在OR理論告訴我們：光在愛因斯坦相對論中扮演著觀測媒介的角色；光速在洛倫茲變換中代表著觀測信息的傳輸速度；光速不變性是一種觀測效應(yīng)，源于觀測局域性. 若能從OR的視角看待光和光速在愛因斯坦相對論中的特殊地位，王令雋先生或許會釋然釋懷，豁然開朗.

可惜，王令雋先生不愿意接受OR理論.

正如《觀測與相對論》所言：“人類對客觀世界的認識，既依賴于觀測，又制約于觀測. 物理學(xué)一切理論或?qū)W說，包括伽利略變換和洛倫茲變換，都與我們的觀測手段或觀測媒介聯(lián)系在一起，無不打上觀測的烙印. ”

Landau和Lifshitz[17]撰寫的《理論物理學(xué)教程》(共10卷)在物理學(xué)教育中頗具影響，其中，特別值得一提的是，Landau和Lifshitz已經(jīng)意識到：光速c在洛倫茲變換中代表信息傳遞速度[17-18]. 然而，他們沒能清晰地意識到：光在愛因斯坦相對論中擔(dān)當(dāng)著觀測媒介的角色；觀測媒介并非必須是光；觀測媒介的速度并非必須是光速.

OR發(fā)現(xiàn)：理論上，任意物質(zhì)運動形式皆可為觀測媒介；不同的觀測媒介可以有不同的信息傳遞速度；不同的信息傳遞速度可能導(dǎo)致不同的理論體系. 伽利略變換和牛頓力學(xué)是理想觀測體系下的理論體系，觀測媒介被理想化，速度無限，信息傳遞無須時間. 洛倫茲變換和愛因斯坦相對論是光學(xué)觀測體系下的理論體系，觀測媒介乃光或電磁相互作用，信息傳遞速度即光速.

基于OR理論，我們可以建立以超聲波為觀測媒介的“蝙蝠相對論”或“海豚相對論”，其觀測信息傳遞速度自然是超聲波的速度. 我們會發(fā)現(xiàn)，這樣的物理模型不僅具有理論意義，還具有現(xiàn)實的和潛在的應(yīng)用價值.

OR理論表明：“自然地，被觀測對象的信息必須借助于一定的媒介，以一定的方式，傳遞至我們的感官或觀測儀器，方能被我們感知或觀測. ”王令雋先生不以為然：“物理量的測量必須通過媒介嗎？”他舉了一些不需要觀測媒介的測量實例. 需要特別指出：“測量”與“觀測”不是同一概念. 觀測是“實時測量”；而王令雋先生此處的測量可謂“離線觀測”. 另一位頗具影響的物理人，針對OR理論提出的觀測局域性問題，表達了與王令雋先生類似的觀點：“人跑不贏汽車，但人可以先走，到前面去等汽車. ”其設(shè)想的觀測途徑同樣地僅僅局限于離線觀測.

離線觀測并非不需要觀測媒介；這一點，王令雋先生似乎也是同意的. 當(dāng)然，離線觀測無須依賴于觀測媒介傳遞觀測信息的速度，不涉及觀測局域性問題和觀測信息延遲問題，等效于理想觀測體系的情形. 因此，如果我們的物理模型可以基于離線觀測數(shù)據(jù)構(gòu)建，那么，它們就必定屬于理想觀測體系下的伽利略- 牛頓理論體系，應(yīng)服從伽利略變換和牛頓定律. 換句話說，這樣的物理模型也只能適用于可離線觀測的情形.

嚴格地說，離線觀測只適用于靜態(tài)觀測：觀測者是靜態(tài)的；被觀測對象也是靜態(tài)的.

然而，物理學(xué)之觀測和實驗，諸如邁克爾遜- 莫雷實驗、電子雙縫干涉實驗、電子- 質(zhì)子對撞實驗、量子效應(yīng)觀測、引力波探測，乃至一切天文觀測，幾乎都需要實時的在線觀測，其中，觀測媒介扮演著不可或缺的角色，觀測局域性問題和觀測信息的非即時性問題無法回避.

因此，觀測媒介傳遞觀測信息的速度必然成為制約物理觀測和物理模型的重要因素，正如光速制約著邁克爾遜- 莫雷實驗，以及洛倫茲變換和愛因斯坦相對論一樣.

6 宇宙的終極速度

王令雋評：“愛因斯坦把光置于一個特別的絕對的位置. ……. 這個特殊位置的最重要的表現(xiàn)就是光速極限原理. 光速成了一切物體速度的上限，不管是絕對速度還是相對速度. 即使光速和光速疊加得出來的還是光速. 其荒謬是顯而易見的. ”

阮曉鋼答：光速不變性假設(shè)有一個直接推論：光速乃一切速度之上限，是宇宙終極速度，是任意物質(zhì)運動形式所不可超越的. 的確，如王令雋先生所思，愛因斯坦相對論之“光速極限”說，是物理學(xué)界至今存在的一個普遍的錯誤認識.

王令雋先生意識到光在愛因斯坦相對論中被賦予了特殊地位，卻不知其本質(zhì)和根源；對于“光速極限”說，認為“其荒謬是顯而易見的”，卻不知其緣何“荒謬”.

OR闡明了其中實質(zhì)性問題之所在.

主流物理學(xué)界的觀念[17-18]是：“由于相互作用的局域性，宇宙存在理論上的極限速度，并且，這一速度必定是不變的. ” 不變的速度(invariant speed)必然導(dǎo)致極限速度或終極速度(ultimate speed). 基于光速不變性假設(shè)，光速是不變性的，因而，宇宙終極速度就是光速.

根據(jù)OR理論：將速度最快的物質(zhì)運動形式之速度視為“不變速度”是一個錯誤.

宇宙并不存在所謂的“不變速度”！

的確，基于局域性原理，可以得出這樣的結(jié)論：第一，所有物質(zhì)運動形式之速度都是有限的；第二，其中必有某種物質(zhì)運動形式的速度是最快的. 然而，根據(jù)OR理論，無論何種物質(zhì)運動形式，無論其速度幾何，當(dāng)其作為觀測媒介為慣性觀測者傳遞被觀測對象之時空信息時，其速度在慣性觀測者看來都是相同的或不變的. 但那并非真實的自然現(xiàn)象或客觀的物理存在，只是一種觀測效應(yīng).

光速在大多數(shù)觀測和實驗中呈現(xiàn)出不變性，原因在于，我們的觀測和實驗大多以光或電磁相互作用為觀測媒介. 然而，特別需要指出：光或電磁相互作用并非我們可加以利用的唯一的觀測媒介. 光擔(dān)當(dāng)觀測媒介時所呈現(xiàn)的速度不變性，并不意味著光速是宇宙極限速度.

愛因斯坦始終認為量子理論是不完備的. 值得注意，愛因斯坦的論據(jù)正是局域性原理(The Principle of Locality)和王令雋先生提到的“光速極限原理”. 愛因斯坦的局域性觀念與其光速不變性假設(shè)聯(lián)系在一起. 愛因斯坦相信：宇宙不存在超距作用，并且，光速是終極速度，不可超越. 1935年，愛因斯坦與同事Podolsky和Rosen一起構(gòu)思了一個著名的思想實驗，史稱EPR佯謬[19]，用以質(zhì)疑量子力學(xué)的完備性. 然而，似乎越來越多的EPR實驗支持量子糾纏現(xiàn)象：宇宙似乎的確存在某種(必定是超光速的)“鬼魅般的超距作用”.

宇宙不存在所謂“不變速度”，因而，也就不存在絕對的“終極速度”，即不存在絕對的速度上限. 然而，根據(jù)OR理論，我們的觀測和實驗存在觀測上的速度極限：觀測媒介速度. 我們不能指望以聲波為觀測媒介，“聽到”超音速物質(zhì)運動；我們也不能指望以光波為觀測媒介，“看到”超光速物質(zhì)運動. 因此，我們也不能指望基于愛因斯坦相對論導(dǎo)出超光速運動關(guān)系. (這涉及引力波和LIGO話題；OR會闡明這一點. )

一直以來，愛因斯坦相對論灌輸給我們的觀念是：光速乃宇宙終極速度，是不可超越的. 然而，物理學(xué)家們基于其內(nèi)稟的自然觀探索超光速物質(zhì)運動的努力卻從未停止過. 王令雋先生對“光速極限原理”的認識，或許，就源于其內(nèi)稟的自然觀. 現(xiàn)在，王令雋先生的觀點得到了OR理論的詮釋.

基于OR理論，超光速物質(zhì)運動是可以期待的！因而，超光速的觀測媒介也是可以期待的！

7 觀測媒介速度不變性

王令雋評：“這里我們注意到的第一個問題是，既然阮教授的‘觀測相對論’的速度疊加公式和愛因斯坦的一樣，也就同樣會導(dǎo)致光速不變，甚至更甚，不僅光速不變，如果用別的媒介觀測，其速度疊加公式也會導(dǎo)致聲速不變，電子流速度不變等等. 而這，是比光速不變還要荒唐，并且很容易實驗證偽的結(jié)論. ……. ”

“既然‘觀測相對論’也邏輯地導(dǎo)致光速不變，就與阮教授的主題‘光速并非真地不變’直接相悖.”

阮曉鋼答：“觀測媒介速度不變性”是OR理論推導(dǎo)得出的邏輯結(jié)論(參見文獻[1]，以及文獻[10-11]). 王令雋先生說：OR之觀測媒介速度不變性比愛因斯坦的光速不變性更荒唐. 這有兩重意思：第一，愛因斯坦的光速不變性假設(shè)很荒唐；第二，OR之觀測媒介速度不變性更荒唐.

首先，作者不敢茍同王令雋先生關(guān)于愛因斯坦光速不變性假設(shè)“荒唐”的說法.

光速不變性假設(shè)自有其合理性，否則，我們將無法解釋愛因斯坦相對論為什么能得到觀測和實驗支持. 光速不變性可追溯至邁克爾遜- 莫雷實驗[20]，其中，光速似乎失去了速度疊加性質(zhì). 光速不變性還表現(xiàn)在光行差現(xiàn)象等其他觀測或?qū)嶒炛? 可見，光速不變性假設(shè)是有實證依據(jù)的.

基于光速不變性假設(shè)，愛因斯坦從理論上導(dǎo)出洛倫茲變換，并建立狹義相對論. 眾所周知，洛倫茲變換原本是一個唯象模型，由Fitzgerald[21]和Lorentz[22]提出. 理論模型與唯象模型一致，映證了光速不變性假設(shè)的合理性和洛倫茲變換的有效性. 這種相互映證關(guān)系是其邏輯自洽性的一種體現(xiàn). 這也是愛因斯坦相對論得到認可的重要原因.

的確，OR理論建立之前，人們一直未能理解光速為什么不變. 這是人們(包括王令雋先生以及許多物理學(xué)家)對于愛因斯坦相對論一直心存疑慮的根本原因. 但由此認為愛因斯坦光速不變性“荒唐”，則是偏執(zhí)的和缺乏理性的.

其次，與愛因斯坦光速不變性假設(shè)不同，OR之觀測媒介速度不變性不是假設(shè)，而是經(jīng)理論推導(dǎo)得出的邏輯結(jié)論，不能簡單地以“更荒唐”蔽之.

觀測媒介速度不變性可謂OR最重要的理論發(fā)現(xiàn)之一，揭示了光速不變性現(xiàn)象的本質(zhì)：光速不變性只是觀測媒介速度不變性的一個特例，僅當(dāng)光作為觀測媒介時成立. 理論上，任何物質(zhì)運動形式皆可為觀測媒介，而非僅僅是光或電磁相互作用.

王令雋先生認為，觀測媒介速度不變性很容易被觀測和實驗證偽. 學(xué)術(shù)討論不能想當(dāng)然或主觀臆斷，而應(yīng)以確實的觀測或?qū)嶒灋閷嵶C依據(jù). 與王令雋先生的想法不同，OR之觀測媒介速度不變性符合人們對物理世界的直觀認識，其合理性易于理解，并且，具有實證依據(jù).

正如《觀測與相對論》已經(jīng)闡明的，與其說邁克爾遜- 莫雷實驗是對光速不變性的支持，不如說是對觀測媒介速度不變性的支持. 在邁克爾遜- 莫雷實驗中，光既是被觀測對象，同時，又是觀測媒介. 因此，根據(jù)OR之觀測媒介速度不變性，光速相對于觀測者必定呈現(xiàn)出不變性.

除光波或光子之外，實驗物理學(xué)家完全有理由或有必要檢驗其他物質(zhì)波或物質(zhì)粒子作為觀測媒介時的速度不變性.

《觀測與相對論》中，作者提出了用電子作為觀測媒介的實驗設(shè)想，以檢驗非光觀測媒介的速度不變性. 可以設(shè)想：用電子替代光子，模擬邁克爾遜- 莫雷實驗，其中，電子既是被觀測對象，同時，又是觀測媒介. 如此，我們不妨想象一下：電子擔(dān)當(dāng)觀測媒介時，電子自身的信息只能由電子自己攜帶和傳遞，正如光子在邁克爾遜- 莫雷實驗中的情形；那么，這時的電子速度會呈現(xiàn)什么狀態(tài)呢？實驗物理學(xué)家可通過實際的物理實驗檢驗之；而現(xiàn)在，我們不妨將其視為一個思想實驗. 類比邁克爾遜- 莫雷實驗中光速所呈現(xiàn)的不變性，我們不難得出這樣的結(jié)論：作為觀測媒介時，電子速度也會呈現(xiàn)出類似的不變性.

通過模擬邁克爾遜- 莫雷實驗，其他物質(zhì)波或物質(zhì)粒子作為觀測媒介時的速度不變性皆可與邁克爾遜- 莫雷實驗中的光速不變性進行類比.

光速不變性是OR之觀測媒介速度不變性的一個特例，僅當(dāng)光擔(dān)當(dāng)觀測媒介時成立，而且，只是一種觀測效應(yīng)；這正說明“光速并非真地不變”，而非王令雋先生所誤解的“直接相?！?

觀測媒介速度不變性既是OR的邏輯結(jié)論，同時，又具有實證依據(jù)，并非王令雋先生想象或期待的那樣“很容易證偽”.

8 OR理論非空中樓閣

王令雋評：“阮教授的‘觀測相對論’中的相對性現(xiàn)象，到底是‘觀測效應(yīng)’還是物理真實？您不妨以聲波為觀測媒介，作為例子，得出相應(yīng)的速度疊加公式、質(zhì)速關(guān)系、相對性動量定義，以及質(zhì)能公式E=mη2. 這里η是聲速. 您對這些結(jié)論有解釋嗎？對這些結(jié)論的證偽，應(yīng)該比對基于光速的相對論的結(jié)果證偽要容易得多. ”

阮曉鋼答：王令雋先生進一步將其對觀測媒介速度不變性的看法，擴展至整個OR理論，并且，同樣表達了兩重意思：第一，愛因斯坦狹義相對論是可以證偽的；第二，OR理論比愛因斯坦相對論更容易證偽，而且，“容易得多”.

正如作者此前闡述過的，物理學(xué)是實證和思辨的矛盾統(tǒng)一體，不能想當(dāng)然或主觀臆斷.

與王令雋先生的看法相反，一百多年來，愛因斯坦的相對論不僅未被證偽，反而得到大多數(shù)觀測和實驗支持. 當(dāng)然，這并不能說明愛因斯坦相對論是放之四海而皆準的終極理論.

OR理論告訴我們：愛因斯坦相對論實則是一個“局部理論”，僅當(dāng)光或電磁相互作用擔(dān)當(dāng)觀測媒介時成立. 在光學(xué)觀測體系中，我們所觀測到的物理現(xiàn)象，自然符合愛因斯坦相對論. 限于人類當(dāng)今的技術(shù)條件，大多數(shù)情形下，我們的觀測和實驗以光或電磁相互作用為觀測媒介. 這正是愛因斯坦相對論得到大多數(shù)觀測或?qū)嶒炛С值脑?

然而，根據(jù)OR理論，非光觀測體系中，愛因斯坦相對論必定會失效. 這時，我們就需要“非光相對論”，例如此前提到的“蝙蝠相對論”和“海豚相對論”. 王令雋先生認為這種以聲波為觀測媒介的情形將證明OR理論是錯誤的.

此前，我們討論了電子作為觀測媒介時的情形. 類似地，我們可以構(gòu)思以聲波為觀測媒介的思想實驗：以聲波替代光波，模擬邁克爾遜- 莫雷實驗，其中，聲波既是被觀測對象又是觀測媒介，自身的信息須由自身攜帶并傳遞. 類比邁克爾遜- 莫雷實驗中光速的情形，我們可以想象，這時聲波的速度也會呈現(xiàn)出類似的不變性.

大家知道，GPS系統(tǒng)通過若干地球同步衛(wèi)星的協(xié)同，實現(xiàn)全球定位. 那么，這些同步衛(wèi)星怎么校準時間，又怎么測定時間和空間呢？這需要借助于愛因斯坦相對論. 這也被視為支持愛因斯坦相對論的有力證據(jù)之一. 其實，與其說這是對愛因斯坦相對論的支持，不如說是對OR理論的支持. 同步衛(wèi)星依靠無線電波通信：其信息媒介即電磁相互作用；觀測媒介速度(η)即光速(η=c). 因此，自然符合愛因斯坦相對論，或者更準確地說，符合OR以電磁相互作用為觀測媒介的情形.

深海，將會是人類未來重要的探索領(lǐng)域；而深海探測，將會是人類未來重要的科考活動. 我國的蛟龍?zhí)査聶C器人已能下潛至水下7 000 m，突破萬米指日可待. 當(dāng)多機器人在深海協(xié)同作業(yè)的時候，它們將面臨與GPS地球同步衛(wèi)星同樣的問題：怎么校準時間，怎么測定時間，怎么測定距離.

水下通信不能指望光或電磁相互作用. 于是，對于深海探測活動中多機器人的協(xié)同作業(yè)，愛因斯坦相對論必定失效！水下機器人必須以超聲波為觀測媒介；相應(yīng)的觀測媒介速度應(yīng)為超聲波在深海中的速度：η≈1 450 m/s. 雖然水下機器人運動速度遠低于衛(wèi)星運動速度，然而，超聲波速度與光速的比更低. 根據(jù)OR理論，較之于光速，深海中的超聲波速度導(dǎo)致的觀測局域性和相對論性觀測效應(yīng)會更為突出. 可見，為了相互間的通信，深海協(xié)同作業(yè)的水下機器人必定需要“海豚相對論”或“超聲波相對論”. 同樣地，潛艇水下協(xié)同作戰(zhàn)，以及潛艇對敵艦或敵潛艇的偵測活動，必定也也需要遵循“超聲波相對論”.

OR理論并非空中樓閣，而是一個符合邏輯的理論模型，并且，具有實證依據(jù)和實際應(yīng)用前景. 實際上，觀測和實驗對伽利略- 牛頓學(xué)說的支持，就是對OR理論的支持；觀測和實驗對愛因斯坦相對論的支持，同樣是對OR理論的支持. “超聲波相對論”將會為OR理論帶來新的實證依據(jù).

“蝙蝠相對論”和“海豚相對論”屬于“亞光速相對論”. 未來，隨著科學(xué)技術(shù)的發(fā)展，人類將會發(fā)現(xiàn)超光速物質(zhì)運動，掌握超光速觀測媒介，發(fā)明超光速觀測體系. 那時，我們就需要“超光速相對論”. LIGO[23-24]的引力波探測活動導(dǎo)致了“引力波天文學(xué)”的概念[25]. 特別注意，引力波天文學(xué)以引力波為觀測媒介，需要服從“引力波相對論”. 按Laplace等[26]和van Flandern[27]等的計算，引力或引力波的速度遠超光速. 因此，引力波可能會成為超光速觀測媒介；而引力波相對論將會是“超光速相對論”. 借助超光速觀測媒介和超光速相對論，我們將會“看”到更為真實的物理世界.

9 OR理論之邏輯演繹

王令雋評：“阮教授提出了一個‘廣義洛倫茲變換’和‘觀測相對論’，其思路，邏輯和結(jié)構(gòu)與愛因斯坦的狹義相對論基本相同，結(jié)論也差不多. 所不同的是，‘觀測相對論’中的相對論因子中的光速c被媒介的速度η所取代. ……. 阮教授的‘觀測相對論’出產(chǎn)了愛因斯坦相對論的幾乎全部系列產(chǎn)品. ”

阮曉鋼答：王令雋先生的意思是，OR理論并無什么創(chuàng)意，無非是對愛因斯坦狹義相對論之邏輯套路的照搬：“結(jié)論也差不多”.

謝謝王令雋先生給作者一個進一步闡述OR理論的機會：OR理論與愛因斯坦狹義相對論因循完全不同的邏輯路線(請參閱文獻[10-11]).

正如作者一開始所強調(diào)的，OR理論不是“制造”出來的. 洛倫茲變換中的光速c被觀測媒介速度η取代，是邏輯演繹和理論推導(dǎo)自然形成的結(jié)果，并非作者有意為之，也非作者初衷.

作者初衷只是希望能賦予光子一點靜質(zhì)量.

許多偉大的物理學(xué)家，包括薛定諤和德布羅意，以及費曼，都曾為尋找光子靜質(zhì)量做出過努力. 在作者的科學(xué)哲學(xué)信仰中，自然辯證法始終扮演著重要角色. 依據(jù)自然辯證法的思想：宇宙是時空與物質(zhì)的矛盾統(tǒng)一體；而時空則是空間與時間的矛盾統(tǒng)一體，物質(zhì)則是質(zhì)量與能量的矛盾統(tǒng)一體. 我不能想象只有能量而無質(zhì)量的物質(zhì)存在. 作者堅信，光子一定存在靜質(zhì)量.

那時，我以為，κ應(yīng)該是不變的，是真正的宇宙極限速度；而c只是κ的一個近似.

沿著這一思路，我著手建立一套公理體系，其中[10-11]：時間定義是最基本的邏輯前提；另有一組波粒二象性條件，給出宇宙極限速度(κ)的定義，并將κ與物質(zhì)波頻率關(guān)聯(lián)起來. 我試圖在這一公理體系下導(dǎo)出能賦予光子靜質(zhì)量的相對論性模型. 然而，我的邏輯演繹進程遇到了障礙：如果κ是不可及的，那么，相應(yīng)的理論推導(dǎo)就無法繼續(xù)下去. 我不得不放棄對κ的限制，允許κ可及，即物質(zhì)運動有可能達到宇宙極限速度κ. 問題似乎又回到了原點，光子仍然沒有質(zhì)量.

于是，我只能暫且放下光子靜質(zhì)量問題.

這時，已經(jīng)建立起來的公理體系令我產(chǎn)生了一種預(yù)感：愛因斯坦的狹義相對論與德布羅意的物質(zhì)波理論有可能在這一公理體系下統(tǒng)一起來. 我想，得不到光子靜質(zhì)量，能將霍金所說的2個“局部理論”統(tǒng)一起來也挺好. 這促使我在已建立的公理體系下繼續(xù)演繹相對論性的慣性時空變換.

我的邏輯演繹和理論推導(dǎo)需要一個物理量，其物理意義很明確：被觀測對象之時空信息相對于慣性觀測者的速度(權(quán)且記作η). 這涉及2個重要問題：第一，誰為觀測者傳遞被觀測對象的時空信息；第二，觀測信息的速度是什么.

理論推導(dǎo)產(chǎn)生了一個有趣的結(jié)論：κ=η！

這意味著：所謂“宇宙終極速度”κ，其實，只是觀測媒介速度η，取決于觀測媒介. 我似乎明白了洛倫茲變換和愛因斯坦相對論為什么會與光速聯(lián)系在一起：光在愛因斯坦相對論中扮演觀測媒介的角色，光速因而顯得不變. 這正是《觀測與相對論》副標題的由來.

最終，OR理論體系得以建立，并且，遠遠超越了作者的預(yù)期：得到了光子靜質(zhì)量；探明了物質(zhì)運動之相對論性的本質(zhì)和根源；概括統(tǒng)一了伽利略變換和洛倫茲變換；概括統(tǒng)一了愛因斯坦狹義相對論和德布羅意物質(zhì)波論. 特別需要指出，OR理論體系很快會開展至愛因斯坦廣義相對論.

特別需要指出，OR理論與愛因斯坦狹義相對論具有完全不同的邏輯. 《觀測與相對論》只是OR理論體系的一個子篇：粒子動力學(xué). 的確，為了簡明，《觀測與相對論》直接以“觀測極限假設(shè)”為邏輯前提，因循愛因斯坦的邏輯，演繹觀測相對論. 其實，“觀測極限假設(shè)”并非假設(shè)；在文獻[10-11]中，它是OR理論的邏輯結(jié)論. 這一點，《觀測與相對論》有說明和解釋；或許，王令雋先生未曾留意，也未曾翻閱過文獻[10-11].

愛因斯坦狹義相對論以光速不變性假設(shè)為邏輯前提，其邏輯演繹進程是逆向的：由果及因；因而，令人知其然而不知其所以然. OR理論以時間定義為邏輯前提，其邏輯演繹進程是正向的：由因及果；因而，令人知其然并知其所以然.

OR理論與愛因斯坦狹義相對論邏輯上的不同，還有一個重要的特征[10-11]：愛因斯坦演繹洛倫茲變換的過程始于空間變換；而OR演繹廣義洛倫茲變換的過程卻始于時間變換.

特別需要指出：無須波粒二象性條件，僅用時間定義和簡單性原理，或者，僅用時間定義和相對性原理，OR整個理論體系依然可以導(dǎo)出(參見文獻[10-11]). 或許，這在科學(xué)方法學(xué)上具有重要意義. 恩格斯說：“哲學(xué)是一切科學(xué)的靈魂.”從一定意義上講，原理，往往代表著某種哲學(xué)信仰. OR的邏輯顯示，基于更基本的邏輯前提，物理世界的簡單性和對稱性可以自然地呈現(xiàn)在我們的物理學(xué)理論或物理模型中. 不能說這證明了簡單性原理和相對性原理，但這的確強化了我們對物理世界之簡單性和相對性的認知或信仰.

10 關(guān)于文風(fēng)

王令雋評：“阮教授用了許多英文字頭縮寫，多達十幾個. 文章讀起來像讀密碼，非常吃力. ……. 學(xué)術(shù)交流，最要緊的是用最有效最清晰的語言表達你的思想. 在提出新的理論的時候尤其如此. ”

阮曉鋼答：謝謝王令雋先生的指教. 限于篇幅，同時，為避免反復(fù)調(diào)用同一過長的詞組，《觀測與相對論》使用了過多的縮寫.

對不起，讓讀者和王先生受累了.

11 結(jié)束語

OR，“觀測相對論”，是邏輯和理論的產(chǎn)物.

OR理論以時間定義為最基本邏輯前提，其邏輯線路與愛因斯坦的邏輯線路完全不同. 然而，OR導(dǎo)出的時空變換關(guān)系卻與洛倫茲變換具有完全相同的形式，即所謂“廣義洛倫茲變換”. 廣義洛倫茲變換概括統(tǒng)一了伽利略變換和洛倫茲變換：在玻爾對應(yīng)原理下，既同伽利略變換嚴格對應(yīng)，也同洛倫茲變換嚴格對應(yīng). 并且，OR理論融合了物質(zhì)運動的波粒二象性，統(tǒng)一了愛因斯坦狹義相對論和德布羅意物質(zhì)波論，能一致地導(dǎo)出愛因斯坦公式E=mc2和普朗克方程E=hf，以及德布羅意關(guān)系λ=h/p. 在OR理論體系中，光速不變性不再是一個假設(shè)，而是OR的邏輯結(jié)論，是OR之觀測媒介速度不變性的個例；E=hf也不再是普朗克量子假設(shè)，而是OR理論推導(dǎo)得出的結(jié)果.

新的理論學(xué)說融合舊的理論，概括并統(tǒng)一舊的理論，是其邏輯上有效和理論上正確的一種體現(xiàn).

作者對OR理論體系的論述(包括文獻[1]以及文獻[10-11])，未必十分嚴謹. 然而，OR理論體系在邏輯上是自洽的，其結(jié)論符合人們樸素的自然觀及其對物理世界的直觀認識.

OR理論發(fā)現(xiàn)：宇宙本不存在絕對的終極速度；光速并非真地不變，光子并非真地?zé)o質(zhì)量；伽利略變換和洛倫茲變換是不同觀測體系的產(chǎn)物，在OR理論中嚴格對應(yīng)；愛因斯坦相對論和德布羅意物質(zhì)波論可統(tǒng)一于同一理論體系；一切相對論性現(xiàn)象皆觀測效應(yīng)，一切量子效應(yīng)皆觀測效應(yīng)；客觀上的同時性是絕對的，時間旅行之類可休矣；時空并不真的彎曲，蟲洞或時空隧道之類可休矣；海森堡的不確定性只是觀測上的不確定，如愛因斯坦所言，上帝果真不擲骰子；普朗克常數(shù)h只是更廣義的物質(zhì)波常數(shù)hη之特例：hc=hηη.

原來，真實的物理世界依然是伽利略和牛頓為我們描述的永恒宇宙和絕對時空.

作者真誠地歡迎并感謝讀者對OR理論的質(zhì)疑和批判. 建議質(zhì)疑和批判OR理論的讀者正式地和直接地向《北京工業(yè)大學(xué)學(xué)報》或者其他學(xué)術(shù)期刊投稿. 物理學(xué)是思辨和實證的矛盾統(tǒng)一體. 就物理學(xué)之學(xué)術(shù)研討而言，作者贊成這樣的文風(fēng)：思辨以邏輯和理論為依據(jù)；實證以觀測和實驗為依據(jù).

OR理論并非空中樓閣. 作者相信，OR理論經(jīng)得起邏輯和理論推敲，經(jīng)得起觀測和實驗檢驗. 我們的物理學(xué)家們?nèi)缛裟芤苑e極的心態(tài)，從OR的視角觀察物理世界，或許，會豁然開朗，并且，會有新的認識和新的發(fā)現(xiàn).

時間和歷史會給出答案.

致謝

作者再次真誠地感謝王令雋先生對OR理論的評論和批判. 同時，作者感謝《北京工業(yè)大學(xué)學(xué)報》編輯部，感謝他們?yōu)榘l(fā)表《觀測與相對論》以及為推動OR理論之學(xué)術(shù)討論所做出的巨大努力. 正如王令雋先生評論所說：“這是難能可貴的.”

Response toOn“ObservationalRelativity”

RUAN Xiaogang

(Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China)

Abstract: Here, the author responds to Mr. WANG Lingjun’sOn“ObservationRelativity”, further clarifies the basic idea and logic of observation relativity, especially indicates the logical self-consistency of observation relativity and its empirical basis.

Keywords: special relativity; general relativity; invariance of light speed

Einstein’s theory of relativity has revealed the relativistic phenomena of matter motion and has been supported by almost all observations and experiments since its establishment. However, to this day, our physics still cannot explain why the speed of light is invariant and why matter motion presents relativistic phenomena. Einstein’s relativity, both the special and the general, has been established for more than 100 years. After all, human’s physics still has to continue: for relativistic phenomena, we cannot stagnate in such a state where we know what but do not know why.

JournalofBeijingUniversityofTechnologypublished in the first issue of 2020 the author’s article entitled “Observation and Relativity: Why is the Speed of Light Invariant in Einstein’s Special Relativity?”[1](“Observation and Relativity” for short) that states a new theory: observational relativity (OR for short). OR theoretically proves that the speeds of observation media are observationally invariant, in which the invariance of light speed is only a special case when light or electromagnetic interaction acts as the observation medium. According to the theory of OR, all theories of physics are rooted in observation, and different observation systems lead to different theoretical systems: the Galilean transformation and Newton’s laws are the products of the ideal observation system, while the Lorentz transformation and Einstein’s relativity are the products of the optical observation system. The theory of OR suggests that all relativistic phenomena, including the invariance of light speed, are observational effects that are rooted in observational locality, rather than objective and real natural phenomena.

Now, for the relativistic phenomena of matter motion, the theory of OR makes us know not only what but also why.

Not surprisingly, since the launch of Observation and Relativity on China National Knowledge Internet on Sept. 10, 2019, Many readers (including senior physicists) have commented on and questioned the theory OR. An authoritative physicist as a member of the Chinese Academy of Sciences criticized in a word, “It is totally wrong to attribute the theory of relativity to observational effects!”

First of all, the author sincerely thanks the readers who critique or question the theory of OR. Anyway, it is the honor of both OR and the author that the theory of OR can gets your critique and attention.

WANG Lingjuan, a professor at the Tennessee University, USA, is the first physicist who wrote a formal letter toJournalofBeijingUniversityofTechnologyto comment on and question the theory of OR. Mr WANG has great attainments and academic influence in the field of theoretical physics; his comments and critiques on the theory of OR are of profound significance, and worth thinking about.

The following isthe author’s response to Mr WANG’sOn“ObservationalRelativity”, which makes a little extension for replying other’s similar comments or critiques on the theory of OR.

1 OR is not artificial

WANG’sComment: “IhighlyappreciatethespiritofchallengingauthorityandthecourageofcritiquebyProf.Ruanandthereviewer. ….OnlywhenthespiritofscientificcritiqueestablishedinRenaissanceisreinstalled,wecanobjectivelyevaluatethemultitudeoffundamentalproblemsoftheoreticalphysicsof20thcenturyandgetoutoftheabyss.ItiscommendablethattheJournalofBeijingUniversityofTechnologypublishedthecritiqueonrelativitybyProf.Ruan.Itisasignthattherearescholarscapableofindependentthinkingwithintheestablishment. ”

RUAN’sResponse: Thank you Mr WANG for your encouragement.

It should be noted thatthe theory of OR has nothing to do withtheestablishment, and only involves pure academic issues; on Einstein’s relativity, the view of domestic physics circle is no difference from that of the foreign physics circle.

The theory of OR is not acritiqueof Einstein’s relativity whether in terms of its original intention or conclusion. The aim of science is not to critique. Science cannot takecritiquingas its springboard, let alonecritiquingfor the sake ofcritiquing.

There is no doubt that Einstein’s relativity is one of the greatest achievements in the history of human physics. The theory of OR is compatible with Einstein’s relativity. Actually, the theory of OR is the inheritance and development of Einstein’s relativity.

However, as Hawking[2]said in hisABriefHistoryofTime: “Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. ” OR suggests that Einstein’s relativity is apartialtheorythat is true if and only if our observation systems employ light or electromagnetic interaction as the observation medium.

In particular, the theory of OR is not artificial, let alonedesignedandmanufacturedfor opposing or critiquing Einstein’s relativity. OR is the product of logic and theory, and an inadvertentdiscovery.

2 All relativistic effects are observational effects

WANG’sComment: “Interpretingrelativityas‘observationaleffect’istohidetheessenceofrelativity. ….WasthedisasterofHiroshimaandNagasakimerelyan‘observationaleffect’insteadofphysicalreality?Canyoucreateauniversesimplybyanobservation? ….Theargumentof‘observationeffect’ofrelativityexistedlongtimeago.Prof.Ruandidnotstartthisschool. ….Such‘criticism’couldnotexplaintheinconsistenciesofrelativity.Moreover,itmightbemisledtotheframeworkofrelativityandrepeatthesamemistake. …. ”

“Allinall,thetheoryofrelativityanditsconclusionsarerevolutionarytheoriesdrasticallydifferentfromtheclassicalphysics.Itcannotbesimplyexplainedasmerelyobservationaleffect. ”

RUAN’sResponse: Mr WANG questions OR’s corollary thatallrelativisticeffectsareobservationaleffects, and expresses the same view as the authoritative physicists mentioned earlier.

Before the establishment ofthe theory of OR, the author had no idea thatrelativisticeffectsareobservationaleffects. It is OR’sdiscovery, OR’s logical consequence, and the result of theoretical derivation, rather than the author’s subjective cognition or personal assertion.

OR is a theoretical model of matter motion, which is based on both speculative study and empirical study. There are two proper approaches to critiquing or questioning a theoretical model of physics: one is empirical, the other is speculative. We can either deny it directly with counterexamples from observations and experiments, or deny its logical and theoretical validity by demonstrating the mistakes in its logical deduction and theoretical derivation. However, we cannot repudiate the theory of OR only based on subjective cognition or personal assertion.

Indeed, as Mr WANG says, “The argument of ‘observation effect’ of relativity existed long time ago. Prof. RUAN did not start this school. ” However, those are merely personal assertions based on subjective cognition, not the products of logic and theory, and have not yet formed a theoretical system or physical model comparable to the theory of OR. Still, there is one point worth thinking about: when advocating that “relativistic effects are observational effects”, they (among them are some senior physicists) did not seem to worry about triggering the paradox that “observation created the universe” or that “atomic bomb explosions were observational effects”.

Indeed, many physicists believe that the huge energy released by atomic bombs can be explained by Einstein’s mass-energy formulaE=mc2: mass can be transformed into energy, and a little mass means a huge energy. There are even reports that scientists have found that the mass of matter decreases after atomic bomb explosions. (It is hard for us to imagine how scientists can measure the masses of matter before and after atomic bomb explosion. )

Actually, Einstein’s mass-energy formula is only one of the relations in his special relativity, which has nothing to do with nuclear physics. Atomic energy, also known as nuclear energy, is the inherent energy of the nuclei of atoms, which is related to strong interaction and has nothing to do with Einstein’s relativity. The huge energy generated in the instant of atomic bomb explosion comes from the release of the inherent energy of countless atoms by chain reaction, which has nothing to do with the mass of matter. There is a saying in the Wikipedia entry onMassEnergyEquivalence[3]: “some people think that this formula directly leads to the design and manufacture of atomic bombs. But in fact, the mass-energy formula has no direct or indirect promotion to the theory, design, and manufacture of atomic bombs. It is only one of the interpretation tools used by someone to explain the principles of atomic bombs. ” Isaackson[4]said in hisChainReaction:FromEinsteintotheAtomicBomb: “Contrary to common belief, Einstein knew little about the nuclear particle physics underlying the bomb. ” In Einstein’s own words in his letter to von Laue[5]: “As to the atomic bomb and Franklin Roosevelt, what I did was just sign a letter drafted by Szilard to the President, seeing that the danger that Hitler might first have the atomic bomb. ”

Einstein’s relativity deems that relativistic effects are objective physical reality and the inherent characteristics of matter motion. This has become the academic view of mainstream physics circle, because Einstein’s relativity, including the special and the general, has been tested for over one century, and supported by almost all observations and experiments. However, as Adrian Cho[6], a commentator of Science, remarked in hisSpecialRelativityReconsidered(for the occasion of the 100thanniversary of Einstein’s special relativity): “So why are there so many people trying to prove it wrong?”

Such a successful special relativity is still being called into question. The root cause is that people cannot understand why the speed of light is invariant and why matter motion exhibits relativistic effects.

People’s knowledge of the invariance of light speed dates from the Michelson-Morley experiment, which is itself a relativistic effect of matter motion.

Note that the invariance of light speed is the logical presupposition of Einstein’s relativity. Therefore, Einstein’s relativity itself cannot explain why the speed of light is invariant and why the matter motion exhibits relativity effects.

The theory of OR has discovered theessence and root of the relativistic effects of matter motion: all theories of physics are dependent on and restricted by observation; all relativistic effects of matter motion are observational effects. This is the meaning of the word “observational” in observational relativity.

In a sense, it is the most important discovery of OR thatallrelativisticeffectsareobservationaleffects.

OR has theoretically derived the invariance of observation-medium speeds, and revealed the root cause of the invariance of light speed in the Michelson-Morley experiment: light plays the role of the observation medium in the Michelson-Morley experiment; the so-called principle of the invariance of light speed is true if and only if light or electromagnetic interaction acts as the observation medium.

Some readers have misunderstood that the theory of OR completely denies the objective reality of relativistic phenomena of material motion. In particular, the theory of OR only means that: 1) our physical observations and physical models based on observations present observational relativistic effects because of being restricted by observational locality; 2) our observations and physical models not only reflect the real material existence and objective physical reality, but meanwhile also contain observational effects. The lower the observation-medium speedηis, the more significant the observation locality and the observational relativistic effects are. The general Lorentz factorΓ(v,η) of OR is the representation of relativistic degree, which can be divided into two parts by Taylor series:Γ(v,η)=Γ∞+ΔΓ(v,η), where?！?1 is the Galilean factor representing objective physical reality, and is absolute and invariant; while, ΔΓis the observation-effect factor representing observational effects, depends on the observation-medium speedηand the matter-motion speedv. There is no observational effect if ΔΓ=0; the larger the ΔΓ, the more significant the observational effect. In the idealized case (such as the case of Galilean-Newtonian theoretical system),η∞,Γ∞=1, and ΔΓ=0: the Galilean transformation and Newton’s laws do not involve observational effects. However, In the optical observation system,η=c<∞ and ΔΓ>0: the Lorentz transformation and Einstein’s relativity involve observational effects.

So, the real physical world is not the relative spacetime described by Mach and Einstein, but the absolute spacetime described by Galileo and Newton.

It is worth noting thatthe general Lorenz transformation in the theoretical system of OR unifies the Galilean transformation and Lorentz transformation, and under Bohr’s correspondence principle[7], strictly corresponds to the both: ifη=c, the general Lorentz transformation reduces to the Lorentz transformation; ifη=∞, the general Lorentz transformation reduces to the Galilean transformation. Such a strict correspondence corroborates the logical rationality and theoretical validity of the general Lorentz transformation and the theory of OR from one aspect.

The mission of science is to explore the unknown, the most fundamental of which is to find out the essence behind natural phenomena, that is, to know why. Now, OR makes us not only know what, where, when and how, but also know why matter motion exhibits relativistic effects in our observation. With the theory of OR we have finally understood that: light plays the role of observation medium in Einstein’s relativity; all relativistic effects, including the invariance of light speed, the relativity of simultaneity, time dilation and length contraction, and even spacetime curvature and quantum effects, are observational effects.

3 On the prerequisites of special relativity

WANG’sComment: “Prof.Ruanasserts: ‘Basedonthehypothesisofinvarianceofspeedoflight,EinsteinsuccessfullyderivedLorentztransformation,establishedspecialrelativity,revealedtherelativisticphenomenaofspacetimeandmatter.Theinvarianceofspeedoflightisnotonlythefoundationofspecialrelativity,butalsooneofthefundamentalpremisesofgeneralrelativity.’Itisanoverstatement.”

“Firstofall,onecouldnotderiveLorentztransformationsimplybasedontheinvarianceofspeedoflight. ….”

RUAN’sResponse: Mr WANG says: “More hypotheses must be added to do that. For example, the transformation must be assumed to be linear. Linearity of a transformation is not self-evident. There is no reason to restrict a transformation to be linear. ” He means to criticize the author’s ignorance of Einstein’s special relativity, although this has nothing to do with whether or not the theory of OR is validity.

Asis known to all, Einstein’s special relativity has two principles as its logical prerequisites: the first is the principle of the invariance of light speed; the second is the principle of relativity. Actually, it has still the little-known third: the principle of simplicity[8].

The linear transformation mentioned by Mr WANG should be attributed to the principle of simplicity; according to Einstein himself, it should be attributed to the homogeneity of spacetime[9]: “In the first place it is clear that the equations must be linear on account of the properties of homogeneity which we attribute to space and time. ” If he was more careful, Mr WANG could read the contents of the linear transformation of spacetime inObservationandRelativity. There is a more detailed exposition on the principle of simplicity and the linear transformation of spacetime in References [10] and [11]. Mr WANG might as well read it a little if interested.

By the way, References [10] and [11] have described the original and complete logical deduction of OR, in which, starting from the more basic prerequisites, OR has directly deduced the Lorentz transformation in differential (not algebraic) form without the principle of simplicity and the hypothesis of linear transformation. (This involves Mr WANG’s question about the relationship between OR’s logic way and Einstein’s logic way, which the author will response later on. )

4 Hypothesis of the invariance of light speed and Einstein’s general relativity

WANG’sComment: “Next,theinvarianceofspeedoflightisnotoneofthefundamentalpostulationsofgeneralrelativity,havingnothingtodowiththeconstructionofEinstein’sfieldequation.Asamatteroffact,generalrelativitydirectlycontradictstheinvarianceofspeedoflight.Itcanbeeasilyshown. ….”

RUAN’sResponse: Mr WANG means to criticize the author’s ignorance of Einstein’s general theory of relativity, although this also has nothing to do with whether or not the theory of OR is validity.

Mr WANG offers aspeed formula of light in gravitational fields derived from the Schwarzschild metric[12]:v=dr/dt=±(1-rs/r)c, to show that the speed of light is variant in gravitational fields, and then asserts that the invariance of light speed is not one of the logical prerequisites of Einstein’s general relativity.

According to Einstein’s general theory of relativity, the speed of light indeed depends on the position in gravitational fields, even without the Schwarzschild metric. However, this does not mean to exclude the invariance of light speed from the list of the logical prerequisites of Einstein’s general theory of relativity. Perhaps, Mr WANG did not pay much attention to the contents of Schwarzschild metric and curved spacetime inObservationandRelativity. According to the theory of OR,curvedspacetimeis also an observational effect caused by the observational locality of light as the observation medium.

As the story goes, Eddington was asked: “People says there are only three persons in the world who really understand Einstein’s general theory of relativity. Is that true?” “So, who is the third?” retorted Eddington at once. Eddington meant that only two persons understood Einstein’s general theory of relativity: one was Einstein himself who established the general theory of relativity; the other was Eddington himself. There is no way to verify the authenticity of such stories; however, they seem reasonable.

Einstein’s general theory of relativity has been established for more than 100 years. However, people (involving senior physicists, and those who specialize in general relativity or write textbooks for general relativity) still hold many ambiguous views about general relativity. As for whether or not the invariance of light speed is one of the logical prerequisites of Einstein’s general relativity, the relevant interpretations are still ambiguous, and even self-contradictory.

According to Reference [13], Einstein ever said: “The speed of light is a function of the position in gravitational fields; the principle of the invariance of light speed in vacuum must be modified. …. The principle of the invariance of light speed is still applicable to this theory, but it is no longer understood as the basis of relativity theory as usual. ” (It seems that Einstein himself was also a little vague about whether or not the invariance of light speed is one of the logical prerequisites of Einstein’s general relativity.) Accordingly, LIU Mingcheng and LIU Wenfang[14]thought that it needed to further clarify whether or not the invariance of light speed is one of the logical prerequisites of Einstein’s general relativity. Their conclusions are that: “The principle of the invariance of light speed is still applicable to general relativity, but it is no longer understood as the basis of relativity theory as usual. The speed of light is a function of the position in gravitational fields, which cannot be measured directly. The principle of the invariance of light speed in vacuum becomes clearer after being modified: the intrinsic value of light speed (that is, the measured value in a local inertial frame) is invariant.” This is a little like repeating Einstein’s words; in any case, there is one point in their conclusions worth affirming: “the measured value of light speed is invariant in local inertial frames”.

ZHAO Zheng[15]wrote in hisIntroductoryLecturesonGeneralRelativity: “Einstein thought that, as the inertial frame could not be defined, it was better to cancel its special status in relativity theory, and put the whole theory in the framework of any reference frame. He assumed that the principle of relativity and the principle of the invariance of light speed held in any reference frame, not just in the inertial frame. Then, the special relativity principle has been generalized as the general relativity principle. The principle of the invariance of light speed has also been generalized to any observers: the light speed measured by any observer is exactlyc. ” I cannot believe that Einstein had done such a generalization to the principle the invariance of light speed. Mr WANG’s arguments that question that “TheinvarianceoflightspeedisalsooneofthelogicalprerequisitesofEinstein’sgeneraltheoryofrelativity” seems more suitable for questioning ZHAO’s statements in Reference [15].

LIU Liao and ZHAO Zheng[16]wrote in their book: “In the general theory of relativity, the physical quantities measured in experiments are the intrinsic quantities measured by the standard clock and the standard ruler, not the coordinate quantities. In a static gravitational field, the speed of light in vacuum measured by the standard clock and the standard ruler is the same as that of special relativity: identically equal toc. ” These words seem to mean that the principle of the invariance of light speed holds if and only if light travels in static gravitational fields.

So, is the hypothesis ofthe invariance of light speed one of the logical prerequisites of Einstein’s general theory of relativity?

The answer to this is yes!

Why does the light speedccome into Einstein’s general theory of relativity and Einstein’s field equation? The theory of OR tells us that this is because light plays the role of the observation medium in Einstein’s general theory of relativity, just as in Einstein’s special theory of relativity.

The most interesting logical prerequisite of Einstein’s general relativity is the equivalence principle. The so-called equivalence principle, in short, means that the physical effects of the gravitational field and the inertial force field are locally indistinguishable. However, people (including many physicists) don’t know fully how the equivalence principle works in Einstein’s general relativity.

In particular, in Einstein’s general theory of relativity, the equivalence principle can work only by the aid of the hypothesis of the invariance of light speed. In fact, without the hypothesis of the invariance of light speed, the light speedcwould not emerge in Einstein’s field equation or Einstein’s general theory of relativity.

In the optical observation system, the gravitational spacetimelooksa littlecurved. The geometric property of such acurvedspacetimehas to be formalized by means of differential geometry, in which thecurvedspacetime can be approximated locally by micro inertial spacetimes. Thus, based on the equivalence principle, Einstein could make thecurvedgravitational spacetime locally equivalent toflatinertial spacetime, where the hypothesis of the invariance of light speed holds, and therefore light can transmit observed information at the constant speedc. It reminds us of the conclusion in Reference [14]: “the measured value of light speed is invariant in local inertial frames”. In this waychas been allowed to join in Einstein’s general theory of relativity and the field equation.

So, the hypothesis of the invariance of light speed is not only the logical prerequisite of Einstein’s special relativity, but also the important and essential logical prerequisite of Einstein’s general theory of relativity.

5 Role of observation media

WANG’sComment: “Einsteinplacedlightinanabsolutelyspecialposition.Lightisnothingbuttheelectromagneticwave….Itshouldnotplayanyroleindeterminingthestructureofspace-time.However,Einsteinendowedlightwithapermanentandspecialposition. ….Theabsurdityisquiteevident. ”

“Domeasurementshavetobedonethroughmedia?Whenwemeasurethelengthofatable,wedirectlycompareitwithameterstick.Whenwemeasurethetimebycountingdaysandnights,wemakeuseofthestableperiodofrotationoftheearth.Whenwemeasuretheweightofanobject,wecompareitwiththeweightsandmarksofabalance.Whenwe….Inallthesemeasurements,nomediumisneeded. ”

“Prof.Ruan…h(huán)asfallenintothetrapofdefendersofrelativitydoctrine. ”

RUAN’sResponse: Mr WANG is strongly opposed to Einstein’s endowing light or the speed of light with a special status in special relativity, and at the same time to OR’s theory ofobservationmedia.

Like many physicists, Mr WANG’s confusion lies in that: on the one hand, he subjectively asserts it isabsurdfor Einstein’s relativity to endow light or the speed of light with a special status; on the other hand, he suffers from the inability to comprehend what role light plays in Einstein’s relativity, what the physical significance of light speed is in the Lorentz transformation, and why the speed of light is invariant. Now the theory of OR tells us that: light plays the role of the observation medium in Einstein’s relativity; the speed of light in the Lorentz transformation represents the transmission speed of observed information; and the invariance of the speed of light is an observational effect rooted in observational locality. In case he understands the special status of light in Einstein’s relativity from the perspective of OR, Mr WANG will feel a sense of relief and become enlightened.

Unfortunately, Mr WANG is not willing to accept the theory of OR.

AsObservationandRelativityremarked: “Human cognition of the objective world not only depends on observation but is also restricted by observation. All theoretical systems or spacetime models of physics, including the Galilean transformation and the Lorentz transformation, are linked to our observation means or observation media, and branded with observation. ”

TheCourseofTheoreticalPhysics(ten volumes in total[17]) written by Landau and Lifshitz has a great influence in physics education. In particular, Landau and Lifshitz had realized that: the light speed c in the Lorentz transformation represents the transmission speed of information[17-18]. However, they had not clearly realized that: light plays the role of the observation medium in Einstein’s relativity; the observation medium does not have to be light; the transmission speed information does not have to be the speed of light.

OR discovers that: theoretically, any form of matter motion can be employed as the observation medium; different observation media may have different speeds to transmit observed information; different transmission speeds of observed information may lead to different theoretical systems. The Galilean transformation and Newton’s laws belong to the theoretical system under the idealized observation system, in which the observation medium is idealized: its speed is infinite and it takes no time for observed information to travel. The Lorentz transformation and Einstein’s relativity belong to the theoretical system under the optical observation system, in which the observation medium is light, and the transmission speed of observed information is of course the speed of light.

Based on the theory of OR, we can buildthebattheoryofrelativityorthedolphintheoryofrelativitywhere ultrasonic wave works as the observation medium and the transmission speed of observed information is naturally the speed of ultrasonic wave. We will find that such physical models not only have theoretical significance, but also practical and potential application value.

The theory of OR suggests that: “Naturally, observed information must be transmitted from observed objects to our sensory organs or observation instruments in some manner, or by means of certain media, so that we can perceive or detect the observed objects. ” Mr WANG disagrees: “Do measurements have to be done through media?” He provided some instances of measurement without an observation medium. Noted thatmeasurementandobservationare not the same concept. Observation isreal-timemeasurement; while Mr WANT’s measurement here isoff-lineobservation. On the problem of observational locality presented in OR, another influential physicist expressed a view similar to Mr WANG’s: “One cannot run faster than a car, but he or she can go first and wait for the car in front. ” Actually, the observation he proposed is also limited to off-line observation.

Off-line observation also needs observation media, and Mr WANG seems also to agree to this. Of course, the off-line observation does not have to rely on the speeds of observation media, does not involve of observational locality and the delay of observed information, and is equivalent to the case in the idealized observation system. Therefore, if our physical models can be constructed with off-line observation data, then they must belong to the Galilean-Newtonian theoretical system under the idealized observation system, and should follow the Galilean transformation and Newton’s laws. In other words, such models are only applicable to the case of off-line observation.

Strictly speaking, off-line observation is only applicable tostaticobservation: the observer is static; the observed object is also static.

However, our observations and experiments, such as the Michelson-Morey experiment, the double-slit interference of electrons, the collision experiment of electrons and protons, the observation of quantum effects, the detection of gravitational waves, and all celestial observations, almost need real-time and on-line observation, in which observation media play the crucial role, and observational locality and the delay of observed information are inescapable issues.

So, the speeds of observation media must be a crucial factor that restricts physical observations and physical models, just as the speed of light restricts the Michelson-Morey experiment, the Lorentz transformation and Einstein’s theory of special relativity.

6 Ultimate speed of the universe

WANG’sComment: “Einsteinendowedlightwithapermanentandspecialposition,themostsignificantmanifestationbeingthespeedlimitoflight.Thespeedoflightbecamethespeedlimitofeverything,beitabsoluteorrelative.Eventhesuperpositionoftwophotonspeedsyieldsthesamespeedoflight.Theabsurdityisquiteevident. ….”

RUAN’sResponse: The hypothesis of the invariance of light speed has a direct corollary: the speed of light is the upper limit of all speeds, that is, the ultimate speed of the universe, which cannot be exceeded by any form of matter motion. Indeed, as Mr WANG thinks, the ultimate speed of the universe is a common misconception in today’s physics circle.

Mr WANG realizes that light is endowed with a special status in Einstein’s relativity, but did not realize its essence and root; on the theory of the ultimate speed, he thinks that “the absurdity is quite evident”, but he did not know why it isabsurd.

OR illustrates the essence of the problem.

Mainstream physics circle claims that[17-18]: “Due to the locality of interactions, there exists theoretically an ultimate speed in the universe, and it is invariant.” The invariant speed inevitably leads to the ultimate speed. Based on the hypothesis of the invariance of light speed, the speed of light is invariant. Therefore, the ultimate speed of the universe is the speed of light.

According tothe theory of OR, it is a mistake to take the speed of the fastest form of matter motion asinvariantspeed.

There is noinvariantspeedin the universe!

Indeed, based on the principle of locality, we can draw the following conclusions: 1) the speeds of all forms of matter motion are limited; 2) there must be a form of matter motion with themaximumspeed. However, according to the theory of OR, no matter what form of matter motion, no matter what its speed, when it acts as the observation medium to transmit the spacetime information of the observed object for inertial observers, its speed is invariant or the same relative to different observers. Nevertheless, that is not a real natural phenomenon or objective physical reality, but only an observational effect.

The speed of lightexhibits invariance in most observations and experiments, because we employ light or electromagnetic interaction as the observation medium in most observations and experiments. But note that light or electromagnetic interaction is not the only observation medium we can make use of. The invariance the speed of light exhibits when light or electromagnetic interaction acts as the observation medium does not mean that the speed of light is the ultimate speed of the universe.

Einstein always thought that quantum theory was incomplete. Note that Einstein’s arguments are based on the principle of locality and the theory of the ultimate speed mentioned by Mr WANG. Einstein’s view on locality is connected with his hypothesis of the invariance of light speed. Einstein believed that there was no action at a distance in the universe, and that light speed was the ultimate speed and could not be exceeded. In 1935 Einstein, Podolsky, and Rosen conceived a famous thought experiment, known as the EPR paradox[19], to question the completeness of quantum theory. However, it seems that more and more EPR experiments support the phenomenon ofquantumentanglement: there does seem to bespookyactionatadistancein the universe, and such an action must be superluminal.

The universe has no so-calledinvariantspeed, and therefore has no absoluteultimatespeed, that is, no absolute upper limit of speed. However, according to the theory of OR, there exists the observational limit of speed in our observation and experiment: the speed of observation medium. We cannot expect tohearsupersonic motion by means of sound wave as the observation medium; and we cannot expect toseesuperluminal motion by means of light wave as the observation medium. So, we cannot expect to derive the relation of superluminal motion from Einstein’s theory of relativity. (This involves the topic about gravitational waves and LIGO; OR will illustrate this.)

Always, it has been a delusion fed by Einstein’s relativity to us that: the speed of light is the ultimate speed in the universe and cannot be exceeded. However, inspired by their intrinsic view of nature, physicists have never stopped their efforts to explore superluminal motion of matter. Mr WANG’s view on theultimatespeedof the universe may exactly be due to his intrinsic view of nature. Now, Mr WANG’s view has been illustrated by the theory of OR.

Based on the theory of OR, superluminal matter motion can be expected; so, superluminal observation media can also be expected.

7 Invariance of observation-medium speeds

WANG’sComment: “Thefirstproblemwenoticeisthat,sincetheformulaofvelocitysuperpositioninProf.Ruan’s‘ObservationalRelativity’isthesameasthatofEinstein,itwillleadtotheinvarianceofspeedoflight,evenmore.Notonlythespeedoflightisconstant,itwillleadtotheinvarianceofspeedofsound,speedofelectroncurrentandsoon,ifothermediaareused.Andthisismoreabsurdthantheinvarianceofspeedoflightandmoreeasilyfalsifiable. ….”

“Since‘ObservationalRelativity’logicallyleadstotheinvarianceofspeedoflight,itdirectlycontradictsthemainpropositionofProf.Ruan: ‘Thespeedoflightisnotreallyinvariant’. ”

RUAN’sResponse:Theinvarianceofobservation-mediumspeedsis a logical inference derived from the theory of OR (see References [1], [10] and [11]). Mr WANG asserts that OR’s invariance of observation-medium speeds is more absurd than Einstein’s invariance of light speed. This has two meanings: first, Einstein’s the invariance of light speed is absurd; second, OR’s invariance of observation-medium speeds is even more absurd.

First, the authorcannot agree to Mr WANG’s statement that Einstein’s hypothesis of the invariance of light speed isabsurd.

Einstein’s invariance of light speed has its own rationality, otherwise we cannot explain why Einstein’s relativity has been supported by observations and experiments. The invariance of light speed can be traced back to the Michelson-Morley experiment[20], in which the speed of light seems to lose the property of velocity addition. The invariance of light speed also presents in other observations or experiments such as the aberration of light. So, the invariance of light speed has its own empirical basis.

Based on thehypothesis of the invariance of light speed, Einstein theoretically derived the Lorentz transformation and established his special theory of relativity. As is well known, the Lorentz transformation was originally a phenomenological model proposed by FitzGerald[21]and Lorentz[22]. The theoretical model is consistent with the phenomenological model, which to some extent corroborates the rationality of hypothesis of the invariance of light speed and the validity of the Lorentz transformation. Such mutual corroboration is the embodiment of logical self-consistency, which is also an important reason for Einstein’s relativity to be recognized.

Indeed, before the establishment ofthe theory of OR, people had never been able to understand why the speed of light was invariant. This is the fundamental reason why people (including Mr WANG and many physicists) had their doubts about Einstein’s relativity. But it is radical and irrational to think Einstein’s invariance of light speed is absurd.

Second, different from Einstein’s hypothesis of invariance of light speed, OR’s invariance of observation-medium speeds is not a hypothesis, but a logical conclusion derived in theory, and cannot simply be denied in two word: “more absurd”.

The invariance of observation-medium speeds is one of the most important theoretical discoveries of OR, which brings to light the essence behind the phenomenon of the invariance of light speedt: the invariance of light speed is just a special case of the invariance of observation-medium speeds, and it is true only when light acts as the observation medium. In theory any form of matter motion can be employed as the observation medium, not just the light or electromagnetic interaction.

Mr WANG asserts that OR’s invariance of observation-medium speeds can easily be falsified by observations and experiments. Academic discussion cannot be taken for granted and based on subjective supposition, but should be grounded on reliable empirical basis. Contrary to Mr WANG’s view, OR’s invariance of observation-medium speeds accords with people’s intuitive understanding of the physical world, its rationality is easy to comprehend, and it possesses empirical basis.

As has beenstated inObservationandRelativity, the Michelson-Morley experiment did not provide so much support for the invariance of light speed as for the invariance of observation-medium speeds. In the Michelson-Morey experiment, light is not only the observed object, but also the observation medium. So according to OR’s invariance of observation-medium speeds, the speed of light must exhibit invariance relative to observers.

In addition to light waves or photons, experimental physicists haveevery reason or need to test OR’s invariance of observation-medium speeds by employing other matter waves or matter particles as the observation medium.

InObservationandRelativity, the author proposes an experiment that employs the electron as the observation-medium, so as to test the invariance of the speeds of nonlight observation-media. Suppose that we emulate the Michelson-Morley experiment by the electron instead of the photon, in which the electron is not only the observed object but also the observation medium. So, let’s imagine that: the electron acts as the observation medium, the information of the electron has to be carried and transmitted by the electron itself, just like the case of the photon in the Michelson-Morley experiment; then, what will at that moment the speed of the electron be? Experimental physicists can test it with practical experiments; but for now, we might as well take it as a thought experiment. By analogy with the invariance of the speed of light in the Michelson-Morley experiment, we can logically conclude that the speed of the electron will also exhibit the similar invariance when the electron acts as the observation medium.

Throughemulating the Michelson-Morley experiment, the invariance of the speeds of all other matter waves or particles as the observation medium can be analogized with the invariance of the speed of light in the Michelson-Morley experiment.

The invariance oflight speed is a special case of OR’s invariance of observation-medium speeds, which is true only when light acts as the observation medium and just an observational effect. This exactly shows that “the speed of light is not really invariant”, rather than that “it directly contradicts …” misunderstood by Mr WANG.

Theinvariance of observation-medium speeds is the logical conclusion of OR, and possesses empirical basis, which is not so “easy to falsify” as Mr WANG imagined or expected.

8 OR is not a castle in the air

WANG’sComment: “AretherelativisticphenomenainProf.Ruan’sObservationalRelativitymerelyobservationalphenomenaorphysicalreality?Whydon’tyouuse,forexample,thesoundwaveasthemediumofobservationandderivetheformulaofvelocitysuperposition,mass-velocityrelationship,definitionofrelativisticmomentumandthemass-energyrelationshipE=mη2,whereηisthespeedofsound.Canyouexplaintheseresults?Itshouldbemucheasiertofalsifytheserelationshipsthantheresultsofrelativitybasedontheinvarianceofspeedoflight. ”

RUAN’sResponse: Mr WANG further extends his view on the invariance of observation-medium speeds to the whole theory of OR, and also expresses two meanings: first, Einstein’s special relativity can be falsified; second, the theory of OR is easier to be falsified than Einstein’s relativity, and “mucheasier”.

As stated above, physics is the contradictory unity of speculative study and empirical study, and cannot be taken for granted or based on personal subjective supposition.

Contrary to Mr WANG’s view, for more than 100 years, Einstein’ relativity has not been falsified, but has been supported by most observations and experiments. Of course, this does not mean that Einstein’s relativity is the ultimate theory that is universally true.

The theory of OR suggests that Einstein’s relativity is actually apartialtheory, and is true only when light or electromagnetic interaction acts as the observation medium. Under the optical observation system, the physical phenomena we observe naturally conform to Einstein’s relativity. Limited to the current technology, in most cases, our observations and experiments employ light or electromagnetic interaction as the observation medium, which is the reason why Einstein’s relativity has been supported by most observations or experiments.

However, according to the theory of OR, Einstein’s theory of relativity must be invalid in non-optical observation systems. So, we need the non-optical theories of relativity, such as the bat and dolphin theories of relativity. Mr WANG believes that the case where sound act as the observation medium will demonstrate that the theory of OR is wrong.

Previously, we discussed the case of the electron as the observation medium. Similarly, we can conceive a thought experiment with sound as the observation medium: to emulate the Michelson-Morley experiment with sound instead of light, where sound is both the observed object and the observation medium, and the information of sound has to be carried and transmitted by sound itself. By analogy with the invariance of the speed of light in the Michelson-Morley experiment, we can logically imagine that the speed of sound will also exhibit the similar invariance when sound acts as the observation medium.

We all know that the GPS system carry on global positioning through the cooperation of many synchronous satellites. So, how do these synchronous satellites calibrate their times, and how do they measure time and space? That has to depend on Einstein’s relativity. This is also deemed as one of the strong evidences supporting Einstein’s relativity. In fact, this is not so much support for Einstein’s relativity as for the theory of OR. Those synchronous satellites communicate with one another by radio: the observation medium is electromagnetic interaction; the observation-medium speed (η) is exactly the light speed (η=c). So, that must follow Einstein’s relativity, or to be more exact, follow the theory of OR as electromagnetic interaction acts as the observation medium.

In the future, the deep ocean will be an important exploration field for mankind, and the exploration of the deep ocean will be an important scientific activity of mankind. China’s Jiaolong, an underwater robot, has already been able to dive to 7 000 meters underwater; the breakthrough of 10 000 meters is around the corner. When multi robots work together in the deep ocean, they will face the same problems as GPS’s synchronous satellites: how to calibrate their time, how to measure time, and how to measure distance.

Underwater communication cannot depend on light or electromagnetic interaction. So, for the cooperative operation of multi robots in deep ocean, Einstein’s relativity must fail. Underwater robots must employ ultrasonic wave as the observation medium; the corresponding speed of observation medium should be the speed of ultrasonic in the deep ocean:η≈1 450 m/s. Although the speed of underwater robots is much lower than the speed of earth satellites, the ratio of ultrasonic speed to light speed is much lower. According to the theory of OR, the observational locality and the observational relativistic effects are more prominent caused by the speed of ultrasonic than that caused by the speed of light. So, in order to communicate with one another, underwater robots working together in the deep ocean are bound to need the dolphin theory of relativity ortheultrasonictheoryofrelativity. Similarly, the cooperative combat of underwater submarines, and underwater submarines’ detection to enemy warships or submarines, will have to depend on the ultrasonic theory of relativity.

The theory of OR is not a castle in the air. It is a logical and theoretical model with empirical basis, and has practical application prospect. In fact, the support of observations and experiments for the Galilean-Newtonian theory is the support for the theory of OR; the support of observations and experiments for Einstein’s relativity is also the support for the theory of OR. The ultrasonic theory of relativity will provide new empirical evidences for the theory of OR.

The bat theory of relativity and the dolphin theory of relativity belong to subluminal relativity. In the future, with the development of science and technology, mankind will discover superluminal matter motion, grasp superluminal observation media, and invent superluminal observation systems. Then, we must need the superluminal theory of relativity. LIGO’s detection[23-24]of gravitational wave leads to the concept ofgravitationalwaveastronomy[25]. In particular, gravitational wave astronomy employs gravitational wave as the observation medium, and needs to obeythegravitationaltheoryofrelativity. Perhaps, as calculated by Laplace et al[26]and van Flandern[27], the speed of gravity or gravitational wave is far faster than the speed of light. So, gravitational wave may become a superluminal observation medium; the gravitational theory of relativity will be the superluminal theory of relativity. With the aid of superluminal observation media and superluminal theory of relativity, we willseea more real physical world.

9 Logical deduction of OR theory

WANG’sComment: “Prof.Ruanproposeda‘generalizedLorentztransformation’and‘ObservationalRelativity’,thethreadofthinking,logicandstructureofwhicharebasicallythesameasthatofEinstein’sspecialrelativity,withalmostthesameresults.Thedifferenceisthatin‘ObservationalRelativity’thespeedoflightcintherelativisticfactorisreplacedbythespeedofmediumη. ….Prof.Ruan’sobservationalrelativityhasproducedalmostallproductsofEinstein’srelativity. ”

RUAN’sResponse: Mr WANG implies that the theory of OR is nothing more than a copy of Einstein’s logic way of special relativity: “with almost the same results”.

Thank Mr WANG for giving the author an opportunity to further elaborate the theory of OR: the theory of OR follows an original logic way totally different from Einstein’s special theory of relativity (see References [10] and [11]).

As emphasized at first the theory of OR is not artificial. It is the result of logical deduction and theoretical derivation and not intended by the author that, in the Lorentz transformation, the light speedcis substituted by the observation-medium speedη.

The author’s original intention is just to give the photon a tiny bit of rest mass.

Many great physicists, including Schrodinger, de Broglie, and Feynman, made efforts to find the rest mass of the photon. Dialectics of nature plays an important role in my philosophical belief of science. According to the thought of dialectics of nature: the universe is the contradictory unity of spacetime and matter; while, spacetime is the contradictory unity of space and time, and matter is the contradictory unity of mass and energy. I cannot imagine such a sort of material existence or physical reality that has only energy but no mass. The author firmly believes that the photon must possess its own rest mass!

At thatmoment I thought thatκshould be invariant and the real ultimate speed the universe; while,cis only an approximation ofκ.

Following this line of thought, I started work on establishing an axiom system[10-11], in which the definition of time is the most basic logical prerequisite; a set of rules of wave-particle duality are employed to define the ultimate speed (κ) of the universe and linkκto the matter-wave frequency. Under this axiom system, I tried to deduce a relativistic model that could give the photon a tiny bit of rest mass. However, my logical deduction ran into difficulty: ifκwas inaccessible, then the corresponding theoretical derivation could not go on. I had to give up the restriction onκand allow it to be accessible. The problem seems to be back to the origin, and the photon is still massless.

So, I had to temporarily lay aside the rest-mass problem of the photon.

At this time, the established axiom system gave me an intuitive feeling that Einstein’s special theory of relativity and de Broglie’s theory of matter waves might be unified under this axiom system. I thought, even though we could not get the photon’s rest mass, it is good to unify the twopartialtheoriesthat Hawking referred to. This prompted me to continue to deduce the relativistic transformation of inertial spacetimes under the established axiom system.

My theoretical deduction needed a physical quantity with the explicit physical meaning: the speed (temporarily denoted asη) of the spacetime information of the observed object relative to the inertial observer. This involves two important questions: 1) who is the messenger to transmit the spacetime information of the observed object to the observer; 2) how fast is the observed information.

An interesting conclusion is drawn from the theoretical deduction:κ=η.

This means that, in fact, the so-calledultimatespeedκof the universe is just the speed η of the observation medium, and depends on the observation medium. I seem to understand why the Lorentz transformation and Einstein’s relativity are connected with the speed of light: light plays the role of the observation medium in Einstein’s relativity, so the speed of light appears to be invariant. This is the origin of the subtitle ofObservationandRelativity.

At last, the theoretical system of OR has been established, which is much more than the author’s expectation: the photon gets its own rest mass; the essence and root of relativistic effects of matter motion are revealed; the Galilean and Lorentz transformations are generalized and unified; Einstein’s special theory of relativity and de Broglie’s theory of matter waves are also generalized and unified. In particular, the theoretical system of OR will yet be extended to Einstein’s general theory of relativity.

Itis worth noting that the theory of OR has its own exclusive logic way that is totally different the logic way of Einstein’s relativity.ObservationandRelativityis only a subchapter of the theoretical system of OR: the dynamics of matter particles. For simplicityObservationandRelativitydirectly takesthehypothesisofobservationallimitas the logical premise of OR, and follows Einstein’s logic way to deduce observation relativity. In fact, the hypothesis of observational limit is not a hypothesis: in References [10] and [11], it is OR’s logical inference. This has been explained inObservationandRelativity. Mr WANG might have not paid much attention to References [10] and [11].

Einstein’s special theory of relativity takes the hypothesis of the invariance of light speed as its basic prerequisite, and its logical deduction is in the negative direction: from effect to cause; so, special relativity makes us know only what but not why. The theory of OR takes the definition of time as its basic prerequisite, and its logical deduction is in the positive direction: from cause to effect; so, OR makes us know not only what but also why. There is still an important feature of the logical difference between the theory of OR and Einstein’s special theory of relativity[10-11]: Einstein’s deduction of the Lorentz transformation starts from the transformation of space; while, OR’s deduction of the general Lorentz transformation starts from the transformation of time.

In particular, without the rules of wave-particle duality, the whole theoretical system of OR can still be derived by combining the definition of time and the principle of simplicity or by combining the definition of time and the principle of relativity (see References [10] and [11]). Perhaps, this is of great significance in methodology. Engels ever remarked: “Philosophy is the soul of all sciences. ” In a sense, principles represent people’s philosophical beliefs. OR’s logic way suggests that, based on the more basic logical prerequisites, the simplicity and symmetry of the physical world can naturally present in our physical theories or physical models. We cannot assert that proves the principle of simplicity and the principle of relativity, but that indeed strengthens our cognition or belief in the simplicity and symmetry of the physical world.

10 On writing style

WANG’sComment: “Prof.RuanusesmorethanadozenacronymsReadinghisarticleislikereadingenigma.Itisverydifficult. ….Inacademiccommunication,themostimportantthingistoexpressandexplainyourideaswiththeclearestlanguage.Itismoreimportantwhenyouareproposinganewtheory. ”

RUAN’sResponse: Thank you Mr WANG for your advice. Due to limited space, and to avoid the repeated calls to those overlong phrases,ObservationandRelativityemploys too many acronyms.

I am sorry to bother readers and Mr WANG.

11 Conclusion

OR, i. e. , is, observational relativity, is the product of logic and theory.

The theory of OR takes the definition of time as the most basic logical prerequisite. Its logic way is totally different from Einstein’s logic way. However, OR has derived the general Lorentz transformation that possesses the exactly same form as the Lorentz transformation. In particular the general Lorentz transformation has unified and generalized the Galilean and Lorentz transformations: under Bohr’s correspondence principle, it not only corresponds strictly with the Galilean transformation, but also strictly with the Lorentz transformation. Moreover, the theory of OR has generalized the wave-particle duality, unified Einstein’s special theory of relativity and de Broglie’s theory of matter waves, and uniformly derived Einstein’sE=mc2, Planck’sE=hf, and de Broglie’sλ=h/p. In the theoretical system of OR, the invariance of light speed is no longer a hypothesis, but a logical inference of OR, and a special case of the invariance of observation-medium speeds;E=hfis also no longer a hypothesis, but the result of theoretical derivation.

It is the embodiment of its logical rationality and theoretical validity that a new theory can integrate, generalize, and unify old theories.

The author’s statements of the theory of OR in References [1], [10] and [11] might not be very rigorous. However, the theoretical system of OR is logically self-consistent, and its conclusions conform to people’s simple view of nature and their intuitive understanding of the physical world.

The theory of OR discovers that: there is no absolute ultimate speed in the universe; the speed of light is not real invariant and the photon is not really massless; the Galilean transformation and the Lorentz transformation are the products of different observation systems, and is strictly corresponding in OR; Einstein’s theory of relativity and de Broglie’s theory of matter waves can be unified in the identical theoretical system; all relativistic phenomena are observational effects, and all quantum effects are observational effects; objective simultaneity is absolute, and the theories of time travel and the like can be stopped; spacetime is not really curved, and the theories of wormholes and the like can be stopped; Heisenberg’s uncertainty is only observational uncertainty, and as Einstein’s remarked, God does not play dice with the universe; Planck’s constanthis only a special case of the general matter-wave constanthη:hc=hηη.

It turns out that the real physical world is still the eternal universe and absolute spacetime described by Galileo and Newton.

The author sincerely welcomes and appreciates readers to critique or question the theory of OR. It is suggested that readers who critique or question the theory of OR contribute toJournalofBeijingUniversityoftechnologyor other academic journals formally and directly. Physics is the contradictory unity of speculative study and empirical study. As for as academic discussion in physics is concerned, the author is in favor of such a style of writing: speculative study is based on logic and theory; empirical study is based on observation and experiment.

The theory of OR is not a castle in the air. The author believes that the theory of OR can stand up to logical and theoretical scrutiny, and can stand up to observational and experimental test. Physicists may become enlightened and have new insights and discoveries, if they observe the physical world from the perspective of OR with a positive mentality.

Time will tell and history will judge OR.

Acknowledgements

The author sincerely thanks Mr WANG Lingjuan again for his critiques and comments on the theory of OR. Meanwhile, the author is grateful to the editorial staff ofJournalofBeijingUniversityofTechnologyfor their great efforts in publishingObservationandRelativityand promoting the academic discussion of the theory of OR. As Mr WANG said in his comment: “It is commendable”.

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