Man is an animal,and his happiness depends on his physiology more than he likes to think.        

more than后是不是少了个what?

【答】加上what不是不可以。但是，句子成分发生了改变。

1. 如果加上what，那么，what he likes to think是名词性从句，它跟his physiology平行并列，都作了depend on的宾语。

2. 如果没有what，那么，he likes to think跟depends on his physiology平行并列。