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I'd like to clear up a misconception: there is no fourth dimension.
我想澄清一种误解：第四维的说法是不成立的
As a matter of fact, there is no third dimension, either.
实际上，第三维也是不对的
Now, by that I don't mean that there aren't three dimensions…
我的意思并不是三维是不存在的
there are, but just we can't tell these dimensions apart:
它当然存在。只是我们不能将这些维度看作是独立的：
there's no special direction you can call "the 1st dimension,"
因为我们没有一个特定的方向来表示第一维度
so it doesn't make sense to say "this is the 2nd one," or "what's the fourth one?"
所以，“这是第二个”，或者“第四个是什么”的说法是没有意义的
It's like if you have a jug with three cups of water in it...
这就比如，假设你有一个水壶，里面装了三杯水…
it's easy to tell that there ARE three cups of water, but which is the first cup?
我们就可以说里面有三杯水，但是哪一部分是第一杯？
the second? or the third?
第二杯和第三杯呢？
Those questions don't even make sense!
我们甚至都不能这样提问！
That said, there may be different KINDS of dimensions that you CAN tell apart
不过，可能会存在有不同种类维度的情况
- like if you poured three cups of water and one cup of oil into our dimensions jug.
就像你往这个维度水壶里倒入三杯水和一杯油
Then you could say "I have three dimensions that behave in the same way, and one that behaves a different way."
那么这时候你就可以说“我这有三个维度以一种方式表现，而另一种以另外一种方式表现”
And that's what we mean when we say that we live in three spatial dimensions and one time dimension.
这也就是我们所说的我们生活在三个空间维度以及单个时间维度中
And there's nothing crazy about adding another cup of water so that you'd have four watery cups and one oily cup;
所以如果当我们再倒入另一杯水，我们就很容易理解你有四杯水和一杯油这件事
likewise we can contemplate what the universe would be like if there were FOUR spatial dimensions and one time dimension…
同样的，我们可以思考一个拥有四重空间维度和单个时间维度的宇宙是什么样子…
or in the case of string theory, nine spatial dimensions and one time dimension.
或者弦理论下的九重空间维度和单个时间维度
And while we're at it, it's not even too hard to conceive that there might be two dimensions of time…
讲到这里，我们也许可以设想一下双重时间维度的可能……
but I don't have even have enough of one time dimension to explain that now.
但是我现在甚至都没有足够的单维度时间来向你解释这些。
So if you'd like to try your brain at visualizing a world with four spatial dimensions,
所以，如果你想训练你的大脑具像化四重空间维度的世界
check out the book Flatland or try solving a 4D rubiks cube.
可以去读读《平面国》这本书，或者试试 4D 魔方
