that you have a road that diverges

你在一条岔路上
and you need to know which way to go between these two hypotheses.

你需要知道该在两个假设间做何种选择
What do you need, to know which way to go?

你需要些什么以决定该走哪条路呢
You need a sign,

你需要一个标志
or this was a cross that you mounted at a crossroads.

或这个设置在十字路口上的十字记号
So the Latin name for cross is crux.

因此cross的拉丁名称为crux
Do you see what they call the experiment? Crucial.

你知道他们将实验称为什么吗关键
That's the origin of the word crucial, right?

这是这个词的起源对不对
It's the one that tells you which way to go.

它告诉你该走哪条路
Okay, so here is Isaac Newton and he's holding something.

这是艾萨克·牛顿他拿着某样东西
Can you see what he's holding in his hand?

你看到他手中拿着什么吗
A candle.

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