我向来对宇宙学的一些理论存疑，但由于自己基础知识太薄弱，觉得所有的疑问均源于自己的无知。就像宗教信徒即使对自己信奉的理论体系有疑问，也没有太多底气去打破沙锅问到底：有人给你解释了，你若还是不理解，这时你自己或他人就会告诉你，这是因为你是以凡人的线性思维去试图弄明白，是徒劳的，权威已经有定论了，你省省吧！

昨天在搜索“差分仪”这个词时，不期然撞见了吴裕祥的文章，顿时眼前一亮！关于时光旅行的辩驳，很合我的口味。也许这个问题早就有人提出来过并被解答且证毕了（而且是令人信服的解答，最多加上一句免责声明：“这个理论具有臆测性”），但Hawking那段文字的漏洞怎么解释呢？太好玩了！我退休后要认认真真地研究这些玩意儿。（顺便提一下，文中提及的《科学家谈21世纪》，是我童年时最爱的一本书。）

有关内容黏贴如下：

霍金在《时间简史》中，详细解释事件光锥如下：

“如果有一个光脉冲从一特定的空间的点在一特定的时刻发出，在时间的进程中，它就会以光球面的形式发散开来，而光球面的形状和大小与源的速度无关。在百万分之一秒后，光就散开成一个半径为300米的球面；百万分之二秒后，半径变成600米；等等。这正如同将一块石头扔到池塘里，水表面的涟漪向四周散开一样，涟漪以圆周的形式散开并越变越大。如果将三维模型设想为包括二维的池塘水面和一维时间，这些扩大的水波的圆圈就画出一个圆锥，其顶点即为石头击到水面的地方和时间。

类似地，从一个事件散开的光在四维的空间——时间里形成了一个三维的圆锥，这个圆锥称为事件的未来光锥。以同样的方法可以画出另一个称之为过去光锥的圆锥，它表示所有可以用一光脉冲传播到该事件的集合。” （黑体是我加的。）

因为这段话是如此地重要，是我直斥霍金科学地撒播荒诞的主要依据，我把后面几句他的英文原文抄录在这里：（黑体是我加的。）

“Similarly, the light spreading out from an event forms a (three-dimensional) cone in (the four-dimensional) space-time. This cone is called the future light cone of the event. In the same way we can draw another cone, called the past light cone, which is the set of events from which a pulse of light is able to reach the given event Figure 2:4.”

英文原文比中文译文更清楚地显示了霍金先生不可思议的逻辑混乱和概念偷换！顺便说一下,最后一句话的中文译文是不够妥当的，正确的译文应该是：

“以同样的方法可以画出另一个称之为过去光锥的圆锥，它是许多事件的集合，从这个事件集合一条光脉冲能够到达一给定事件。”

但不管怎么译法，在这几句话里，霍金都说得很明白：未来光锥是一“事件散开的光”在四维的空间——时间里形成的一个三维的圆锥，怎么就能变成了事件集合呢？请读者自己去霍金或者爱因斯坦的著作里找一找，“事件散开的光”怎么就能变成了“事件”本身呢？经过了任何证明吗？还是就这么含含糊糊地说着说着就把上一句说的“事件散开的光”，在下一句里用一个莫须有的“同样的方法”糊弄成了“事件”本身呢？如果是这样，世界上还有比这更不严肃的“科学”推理吗？用这样的所谓“科学”名正言顺地围剿我们的传统文化，是我们可以接受的吗？

我在这里公开请求霍金先生：请您把这光和事件的玄妙的转换解释清楚。用数学也行，用老百姓的语言也行，别这么含含糊糊地蒙着数学的斗蓬变魔术！或者您就明明白白地告诉我们这类没想象力的人，您是在写科学幻想作品，骑着光脉冲去执行爱因斯坦的杀父任务。

我的这些文字是很尖酸刻薄。可是，想起我自己和我这一代人，从小起在做人的道理上被教导得傻不拉叽，读书后在科学的道理上又被这些权威糊弄得昏天黑地，心里怎能没有气？

记得小时候读一本《科学家谈21世纪》，里面讲到如果我们能比光跑得快，就能追上过去追上历史。自那时起就念念不忘，常常就着这话题作儿时的幻想少年的梦。长大后思路开阔了一点，人生阅历多了一点，偶尔再就着这话题想起来，就见到无数的破绽，把它当作不值一谈的少年梦付之秋风。不料今天还要来严肃地讨论它。

我发现了吴先生这段文章里的有个不大不小的问题：他误解了Hawking原文中某一层的意思！首先，“到达一给定事件”应译作“到达这一给定事件”。其次，发出光脉冲的不是事件集合，而是那个事件集里的每个事件，换言之，那个定语从句修饰的是events，而不是set of events。这样就比较容易理解这段话的意思了：光必须有光源，这里姑且把每个光源称为事件。光锥本身是虚的（只有光，没有事件实体），但它的来源是事件实体。

我怀疑Hawking的表述只是不够精准，他可能想说：In the same way we can draw another cone, called the past light cone, which is the product of a set of events from which a pulse of light is able to reach the given event.

他“可能”并不想说，光锥本身是事件！

即便如此，吴先生的质疑依然有效：这个给定事件的未来光锥散发出去形成光球面，这个光球面不是事件，更不是事件集合，但它的过去光锥源头却是事件集合？

这里牵涉到时间维度。事件A的过去光锥不是事件A散发的，而是发生在过去的事件B、C、D、E、F、G的各自光锥射向事件A形成的，因为事件A处于过去这些事件的各自光锥的结合点。

但这里的问题是：往事的“光”，对未来的事件有影响吗？在绝对意义上来说，不可能没有影响。但这是什么性质的影响？假如真的有大爆炸，那么那个事件的过去光锥是什么来源？

我要弄本A Brief History of Time，再读一遍。第一次读没有下功夫。

Date: 25 Nov 09

Venue: Palais des Nations (HQ of UN Office at Geneva)

Occasion: Wushu Performance, hosted by Chinese ambassador to UN Office at Geneva

Immediately after the show, I wrote the following to mark the event. You don't get to see such a performance very often in this neck of the woods.

After an agonisingly verbose, but understandably indispensable (thus graciously suffered by the audience), drone of opening speeches by a few dignitaries, the show begins, not to the rousing gongs and drums that typically usher in a traditional Wushu performance, but to the blasting decibels of a pick-n-mix concoction of Chinese folk music plus revolutionary Peking opera plus Cantopop plus disco beat and what-not.

The emcees (one gorgeous-looking female and one slightly shy but nonetheless presentable male) speak in English and French alternately, but the guy's voice fails to rise above the ambience-critical music throughout the show. Luckily for me, he is the one who speaks French. Obviously, at some subconscious level, the organiser believes the melodies, albeit less than melodious most of the time, are more integral to the show than some feeble commentaries, especially if they are delivered in French.

The emcees introduce the lineup. Impressive! Thirteen national and world champions and the rest, silver medalists. Each performs a short routine of what he or she is best at, as a silent/nonverbal self-introduction. The guy with the lance is a little unfortunate: The shaft breaks in two during that short routine. "I hope he has a spare one", I think to myself. Later, it turns out that he does have a spare one, but the ornamental tassel below the spearhead looks half-shorn, presumably because there isn't enough time for him to fasten all the strands of the tassel in place.

The first proper performance is a warm-up routine. One expression comes to my mind: gravity-defying. When Jet Li's films were introduced to the West, that was the word that the Western media often used to describe his feats. So very apt.

However, as they repeatedly leap into the air and do one somersault after another, I begin to worry: Won't they burn out at this rate? I mean – this is only the first routine. Save your energy, kids!

But I am proven wrong, subsequently. They are bursting with bountiful energy, each jumping higher than the previous person and showing not the slightest fatigue.

Highlights include:

(5) Swordplay by Shen Guangmei, silver medalist at the 11th National Games. Comment: She flows.

(6) Broadsword routine by Zhang Bo, gold medalist at the National Wushu Championship. Comment: Speed backed up by a lot of power.

(9) Double broadswords (wielded by Zhang Li, gold medalist at the 10th National Games) against two lances (in the hands of Ji Taijing, silver medalist at the 11th National Games, and Shen Guangmei, ditto). Comment: Zhang Li would be super efficient in the kitchen with double cleavers. Just imagine two spears darting at you at all angles, like woodpeckers, and you have to fend them off with two pieces of flat metal and eventually snatch away their weapons and chop them in half (hypothetically, I hasten to add)!

(10) Group performance, southern style, by Zhou Jing (gold medalist at the 9th World Wushu Championships and the 7th Asian Wushu Championships) et al. Comment: Yummy! Zhou performs the first form of Wing Chun/Yongchun, at dazzling speed, to make it look more powerful and more entertaining. He also spars with each of his three teammates, using predominantly the Hong style techniques, not Wing Chun. Regrettably, the final stroke is invariably a kick, which is more characteristic of the northern style.

(11) Taiji by Dong Qing (20 years old, gold medalist at the 1st World Junior Wushu Championship and the 2nd Asian Junior Wushu Championship, one of the Taiji performers at the Opening Ceremony of the Beijing Olympics) et al. Comment: Solid training, with inspirational flair. A thorough joy to watch!

There is no intermission, but according to the programme, (1)-(11) is the cluster of competitive styles (competitive in the sense of being performed at national games and international championships). It is followed by a cluster of "traditional" styles. The most impressive among this lot is Xingyiquan (Form-and-Mind Boxing) performed by Zhou Jing, yes, the southern-style guy. Xingyi is one of the three "internal" schools of martial arts, the other two being Taiji and Bagua. Unlike the latter two, Xingyi doesn't readily lend itself to "performance" on stage. But Zhou does a very decent job by demonstrating the essential Xingyi moves while letting the audience sense the power that surges within.

This 30-year-old guy is truly amazing, as he then surprises the audience with a somewhat comical rendition of sparring performance: Hammer versus cudgel, with him brandishing a long-handled hammer and his hopeless opponent taking him on with a pole. And he is not even puffed out when he, quite literally, "nails" his hapless mate in the end!

It is an evening of jolly good fun. Triple thumbs-up to the young performers. I want to shout bravo or encore, but (a) I sit too far away from the stage and I am aware that the emcee, with the help of the PA system, can't even beat the music; and (b) I sit among a group of ladies, so the sheepish side in me gets the better of my other side, whatever that other side is!

QED

食、色，性也。

两者均为手段。

其目的：食-->生存；性-->续存。

共同的终极目的：永生。

在形而下的范畴，永生的必要手段暨唯一手段就是生儿育女。

因为

在形而下的范畴，“灵魂”就是基因，就是DNA承载的遗传信息。

基因传下去了，绵延不断（若可能的话），实体的永生就实现了。

但人生的不如意（苦）和自然的不可知（惑），让人将自我的生存状态分为形而上和形而下这两个域（虽然这个分野是朦胧的，甚至不确知的）。“我”同时并存于这两个域，而“我”的“意识”却在不同的时空点，时而“上”，时而“下”。

不同的人，侧重点亦不同，于是有了几乎只对形而下的自体的生存和续存感兴趣和几乎只对形而上的灵魂的生存和续存感兴趣这两个极端，以及这两个极端之间的无数个频段。

形而上的“我”，是解放者，将物理的束缚解而放之，并为在理论层面上寻找人生意义的人提供一种超脱的空间和机会，去探寻这种理论意义，让主体能够因理论意义的落实而感到安全和充实从而感到更加幸福（同时也可能因探寻的失败而得出否定自体生存的理论意义的结论并由此得出否定“存在”之任何意义的结论）；形而下的“我”，是务实者，务食、色之实，并承载形而上的所有活动。

那些探寻人生的理论意义的努力，通常是以失败告终，但如果你能拐个小弯，接受宗教，则万事大吉。

宗教，就是路旁的一扇扇小门。

而这条路就是寻求“真理”的道路。寻求理论上的人生意义的道路。

反正这条路没有尽头，你迟早会走累。没事儿，总有一种宗教或者某一揽子宗教理论，契合你迄今为止走路的心得，让你产生走到尽头的主观感觉（而筋疲力尽的你也非常需要有权威告诉你，你已经登顶了）。一拍即合。

这就叫“得道”。

得道之后，可以歇一歇，理一理思路，沉淀一下。

只要你的脑袋没坏掉，迟早会再次启动，在貌似没有问题的地方找出新问题，然后继续去寻找答案。

如果你没有退出之前走进去的路边小门，那么此时你就会沿着新的方向前进，一般来说，这个方向就是那个具体的宗教所设定的前提性方向。

如果你找到了一些答案，而且经过验证，可以回答那些新问题，那它们将成为这种宗教的思想库中新的财富。

咦，我是在谈宗教吗？这不是科学的特点吗？

啊哈，原来宗教跟科学，本质上并没有区别。