Que or lequel?

Question

Hi,I have a question regarding "lequel"...I still dont get when to use "que" and "lequel".....There is one sentence i found from online news article and the use of "lequel" in it confuses me..Le racisme, c'est l'idée selon laquelle l'espèce humaine serait composée de plusieurs races différentes.En savoir plus : https://www.1jour1actu.com/info-animee/cest-quoi-le-racismeIt is literally the first sentence of the article and so nothing has been mentioned before that sentence. Regardless the "laquelle" has been used along with "selon", preposition. Also, when I translate it based on a dictionary, it means "according to which". It sounds so weird if i apply it onto the whole sentence. So, my questions are.......1. is it necessary to use "selon laquelle or can I simply use "que" instead? (Like "c'est l'idée QUE l'espèce humaine serait....")2. And just like "dans lequel" which can simply translate as "where(=où)", does "selon lequel" also mean something simple other than its dictionary meaning, "according to which"? I would appreciate for any reply!

Accepted Answer

Selon cette idée... -- according to that idea...l'idée selon laquelle...  -- the idea according to which...l'idée que... -- the idea that...So, yes, there are ways to reword the sentence so that you can use que. But selon laquelle sounds more elegant and, well, "French".