what is conceived to be reality做什么成分?

of what is conceived to be reality 整体才是定语成分 是一个所有格形式
修饰representation
what is conceived to be reality 是典型的名词性从句 做介宾 即介词of 的 宾语
what is conceived to be reality= something that is conceived to be reality
句意是
从本质上来讲,理论是对于被认为是事实的事物的抽象化、符号化的表现形式.