The use of each key in Western music?

Question

I've been looking into variations on the following question: why was X piece written in Y key? For instance, why did Beethoven choose to write the Moonlight Sonata in C# minor? Presumably we can transpose a piece and, in theory anyway, it will still be the same.I know that this question has been asked before, but I'd like to expand on the previous questions asked by other posters. In particular:There are a number of opinions of composers about each key. C major is considered "innocent and childlike", for example, but one source refers to F-sharp minor as "A gloomy key: it tugs at passion as a dog biting a dress. Resentment and discontent are its language.". I disagree with that opinion on F-sharp minor (I find it to be a playful key in which dances "make sense").So I suppose the question really is: how does a composer develop their particular style and thereby attribute certain desirable qualities to each key? For example, I've already chosen F-sharp minor to be a playful, dance-like key and G-sharp minor to be a slow, haunting key. That's my personal opinion, but I can't define why I hold it.

Answer 1

My answer is going to be quite unscientific, yet the reason why it's unscientific is somewhat scientific. My personal posture, due to all of the evidence of imperfections and inconsistencies between the physioacoustic world and western Music Theory, is that I don't believe that there are specific temperaments, or tunning systems, etc. that "allign" more with nature or the universe than others. For this, I'd highly recommend watching the video "A = 432 hz" by Adam Neely on YouTube.

This is why I find myself drifting towards the "agnostic" side of this discussion, and logically conclude that the reason why certain keys feel different than others is not related on how they could be "universally" or physically better than others.

That said, I'm not saying that I hear every key as equal, either. But I honestly don't know and we will probably never know where these opinions exactly come from. We have to be frank: I believe there has to be a percentage of bias (whether socially constructed or personally formulated).

One example of this bias is an experience that I had with a friend who has perfect pitch and is really into how frequencies feel: I play mostly piano, and I have never played any type of wind instrument, nor any type of transposing instrument either.

1. When asked about my favorite keys, I mentioned C minor, Db major, Ab major, and maybe B major (even though I just prefer any key and the specific arrangement will just follow through in the best way).
2. My friend, as an Oboe and Clarinet player, with most of her life dealing with flat keys and always leaning towards the complicated side of things, said something like Bb major, Eb minor, and something else like Gb major.

I'm actually ok with Bb major, but I'm really not feeling the idea of Eb minor. Maybe Eb is one of my least favorite keys to hear... Or to play? ... Isn't it that Eb is not my favorite just because Eb is one of the keys that I play the least on piano?

That thought made me realize that I may clearly have a bias. And if me, somebody with a pretty darn good ear, can have such a subjective bias, why would anyone be more right that others regarding keys? Why did she "coincidentally" pick a bunch of flat keys and no sharp keys at all? (She even mentioned me like 3-4 more, and still no sharp keys); or even simpler keys, after the fact that she likes the complicated stuff?

Also, it may sound absolutely stupid, but I even have the tendency to think of G major as a bright and yellow key. Then, I realize that G in Spanish is "Sol", which means "Sun". Talk about cognitive bias!

I prefer to remain skeptical even to the most expert of the guesses, but I have witnessed why. I do agree with many of the claims that the majority tends to agree (the biggest one of them: D minor being the strongest/most cutting minor key in some way --whether it's by being the saddest, the darkest, or whatever), but I never stop finding surprises in this discussion.