Materialism
noun
The solely things theory is the theory that only things are important. This is also known as materialism.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
母国語でも唯物論について説明できないのに、どうして外国語で説明できるというのか。
I can’t even explain materialism in my native language, so how can I explain it in a foreign language?