Does all Music require knowledge of theory?

I will be active in this topic for sure.

I've recently had an argument with a friend on the topic stated in the name. He claims that you don't need to know anything about music theory to make music, that people make music by just making it.

My opinion on this is that no matter what form of music you play there are ALWAYS rules as to how it should sound or be created. Even in metal there are rules that must be followed. You will never hear any metal band play in any major keys or do a solo in major keys, it's all minor keys. There are specific rhythmic rules that every music follows, you won't hear any metal song that plays in just quarter notes and half notes, it's just not allowed or considered metal. Even in 12-tone music, the most chaotic sounding thing has its own specific guidelines when it comes to composing it. Even rap has rules to follow. Music has rules that must always be followed even if you don't know it by the book a person plays music by what they KNOW has to be done and by how they KNOW it must be done, every once in a while you will have people that expand or even bend rules (for example, Cradle of Filth ) but they all follow the guidelines set for music.

Discuss, if there's a term someone doesn't understand feel free to ask and I will be glad to answer it.