Dear Everyone.
OK, something's telling me this is a stoopid question with an obvious answer but I'm not getting it.
If you want to write a sad song, you're told to use a minor key. BUT....
C Major = A Minor.
G Major = E Minor.
And so on. Every major key - OK, I'm a NOOB!! - has a minor key with exactly the same sharps and flats. So as far as I can see, every major key can be looked at as a minor key and visa-versa.
So when you THINK you're writing in a minor key, you're actually writing in something else's major key and also visa-versa.
So as they're basically both the same, how do you tell which key you're writing in (as it's got the same sharps and flats as another key). As a major key is something else's minor key, can you use it to make parts of a tune sound happy (major) and other parts sound sad (minor) without actually changing key? If you're using what started out as a major key to make parts of a piece sound sad, are you actually changing into the relative minor key (as websites everywhere tell me only minor keys can sound sad) and how do you KEEP it sounding sad (minor!) And finally....
If a key can be either major or minor depending on circumstance, does it matter which key you THINK you're writing in as you're always actually writing in 2 keys simultaneously anyway aren't you - the key you THINK you're using and its relative key, be that major or minor, as they both have the same notes and the same sharps and flats?
I've never gotten this one. I've never REALLY understood the point of having set keys. Why can't you just decide which notes you want sharpened and flattened in your piece, put those sharps and flats in the key signature and have done with it, whether it's something called a 'key' or not? Why the set rules? These last questions are fairly rhetorical btw, I've asked enough above them! But I'd love my puzzlement with the questions above this bit cleared up, just don't get it.
Yours baffledly
Chris.