as purposeless as human evolution is，...

在美国英语中，通常使用as...as...引导让步状语从句，意为“虽然；尽管”。英国英语没有第一个As，也许美国人是为了读起来顺口吧，因为人们习惯了说 as...as...，于是，就在被前置的形容词或副词前面，又加了一个as。

例如：

As cold as it was, we went out.

= Cold as it was, we went out.

尽管天气冷，我们还是出去了。

As successful as he is, he is not proud.

=Successful as he is he is not proud.

他虽成功了，但不骄傲。

As amazing as you already are, you can be even more so.

= Amazing as you already are, you can be even more so.

虽然你已经很了不起了，但你可以更要这样（“这样”指“谦虚”）。