According to the Boshongo people of central Africa，in the beginning there was only darkness，water，and the great god Bumba.
根据中非Boshongo人的传说，世界太初只有黑暗、水和伟大的Bumba上帝。
One day Bumba，in pain from a stomach ache，vomited up the sun. The sun dried up some of the water，leaving land.
一天，Bumba胃痛发作，呕吐出太阳。太阳灼干了一些水，留下土地。
Still in pain，Bumba vomited up the moon，the stars，and then some animals：the leopard，the crocodile，the turtle，and，finally man.
他仍然胃痛不止，又吐出了月亮和星辰，然后吐出一些动物，豹、鳄鱼、乌龟，最后是人。
This creation myth，like many others，tries to answer the questions we all ask. Why are we here? Where did we come from?
这个创世纪的神话，和其他许多神话一样，试图回答我们大家都想问的问题：为何我们在此?我们从何而来?
The answer generally given was that humans were of comparatively recent origin，because it must have been obvious，even at early times，that the human race was improving in knowledge and technology.
一般的答案是，人类的起源是发生在比较近期的事。人类正在知识上和技术上不断地取得进步。
So it can’t have been around that long，or it would have progressed even more.
这样，它不可能存在那么久，否则的话，它应该取得更大的进步。这一点甚至在更早的时候就应该很清楚了。
For example，The Book of Genesis placed the creation of the world at 9 am on October the 23th，4，004 BC.
例如，《创世纪》把世界的创生定于公元前4004年10月23日上午9时。
On the other hand，the physical surroundings，like mountains and rivers，change very little in a human life time.
另一方面，诸如山岳和河流的自然环境，在人的生命周期里改变甚微。
They were therefore thought to be a constant background，and either to have existed for ever as an empty landscape，or to have been created at the same time as the humans.
Not everyone however，was happy with the idea that the universe had a beginning. For example，Aristotle，the most famous of the Greek philosophers，believed the universe had existed forever.
Something eternal is more perfect than something created. He suggested，the reason we see progress was that floods，or other natural disasters，had repeatedly set civilization back to the beginning.
The motivation for believing in an eternal universe was the desire to avoid invoking divine intervention，to create the universe，and set it going. Conversely，those who believed the universe had a beginning，used it as an argument for the existence of God，as the first cause，or prime mover of the universe.
If one believed that the universe had a beginning，the obvious question was：What happened before the beginning? What was God doing before He made the world? Was He preparing Hell for people who asked such questions?
He called that the thesis. On the other hand，if the universe had existed forever，why did it take an infinite time to reach the present stage?
他将此称为正题。另一方面，如果宇宙已经存在了无限久，为什么它要花费无限长的时间才达到现在这个阶段。
He called that the antithesis. Both the thesis，and the antithesis，depended on Kant’s assumption，along with almost everyone else，that time was Absolute.
他把此称为反题。无论正题还是反题，都是基于康德的假设，几乎所有人也是这么办的，那就是，时间是绝对的
That is to say，it went from the infinite past，to the infinite future，independently of any universe that might or might not exist in this background.
In this，space and time were no longer Absolute，no longer a fixed background to events. Instead，they were dynamical quantities that were shaped by the matter and energy in the universe.
They were defined only within the universe，so it made no sense to talk of a time before the universe began.
它们只有在宇宙之中才能够定义。这样谈论宇宙开端之前的时间是毫无意义的。
If the universe was essentially unchanging in time，as was generally assumed before the 1920s，there would be no reason that time should not be defined arbitrarily far back.
Any so-called beginning of the universe，would be artificial，in the sense that one could extend the history back to earlier times.
人们总可以将历史往更早的时刻延展，在这个意义上，任何所谓的宇宙开端都是人为的。
Thus it might be that the universe was created last year，but with all the memories and physical evidence，to look like it was much older.
于是，情形可以是这样，这个宇宙是去年创生的，但是所有记忆和物理证据都显得它要古老得多。
This raises deep philosophical questions about the meaning of existence. I shall deal with these by adopting what is called the positivist approach.
这就产生了有关存在意义的高深哲学问题。我将采用所谓的实证主义方法来对付这些问题。
In this，the idea is that we interpret the input from our senses in terms of a model we make of the world. One can not ask whether the model represents reality，only whether it works.
A model is a good model if it first，interprets a wide range of observations，in terms of a simple and elegant model.
首先，如果按照一个简单而优雅的模型可以解释大量的观测;
And second，if the model makes definite predictions that can be tested，and possibly falsified by observation.
其次，如果这个模型作出可能被观察检验，也可能被证伪的明确预言，这个模型即是一个好模型。
We do not yet have a good theoretical understanding of the observations that the expansion of the universe is accelerating again，after a long period of slowing down.
我们观察到，宇宙的膨胀在长期的变缓之后，再次加速。对此理论还不能理解清楚。
Without such an understanding，we can not be sure of the future of the universe. Will it continue to expand forever? Is inflation a law of Nature? Or will the universe eventually collapse again?
缺乏这种理解，对宇宙的未来还无法确定。它会继续地、无限地膨胀下去吗?暴胀是一个自然定律吗?
New observational results and theoretical advances are coming in rapidly. Cosmology is a very exciting and active subject.
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