他使用了这样一个类比：心智无形且不可见，就像天空一样。

He used the ___analogy of the mind, which has no form and is invisible, being like the sky.

这个类比与人类及其创造物——机器——之间的依赖关系有着惊人的相似之处。

The ___analogy bears striking similarities to the relationship of dependency between humans and their construct, the machines.

人们经常将人脑和计算机进行类比。

People often draw an ___analogy between the human brain and a computer.