They must realize that their knowledge is mostly perceptual and partial and that they lack rational and comprehensive knowledge in other words, they lack theory and their knowledge, too, is relatively incomplete.

• 他们须知自己的知识是偏于感性的或局部的，缺乏理性的知识和普遍的知识，就是说，缺乏理论，他们的知识也是比较地不完全。