No one could doubt his ability to learn abstract knowledge.

没人置疑他在学习抽象知识方面的能力。

youdao

Such abstract knowledge is above children's comprehension.

这么抽象的知识，孩子是不能理解的。

youdao

"These are very rapid inductive leaps to abstract knowledge that we see children making, and that we'd like to have in computers, " he says.

FORBES: Magazine Article

Semantic knowledge involves general, abstract concepts.

MSN: How the brain turns reality into dreams

People rely on their spatial knowledge to build many other more complex or abstract representations including time, number, musical pitch, kinship relations, morality and emotions.

WSJ: Does Language Influence Culture?