The capacity of the human mind for formulating and solving complex problems is very small compared with the size of the problems whose solution is required for objectively rational behavior in the real world.

探索是人类精神的真正本质。

一个奇怪的事实是，在大西洋两岸发现了极其相似的动植物，但没有人对这一现象给出令人满意的解释。

有些东西是很难找到的。