Pianos are sentimental and thoughtful. Acoustic guitars are peaceful and playful. Electric guitars are aggressive. Violins are sad. Fiddles are happy. Minor key signatures are sad. Majors are happy.
These are the lessons learned through conditioning and carefully planned conformity. While I cannot prove there is nothing inherently emotive in a single tone, I can say this sentiment that may or may not exist is perpetuated by its presence in a repetitiously similar context.
Advocates of theories that would indicate an automatic emotional effect would state that the first time a minor third was played on stones in an African cave, Grog heard "sad." Perhaps simplifying my language to monosyllabic idiocy when stating the opposing theory is a snide way of making my argument appear more intelligent, but if elected officials do it when discussing matters that go beyond mere life and death, then what the hey?
I am quite apparently inclined to disagree. Having heard minor chords in context with sad lyrics, sad moments in theater and film, even the problem-introducing first halves of commercials for years upon years, we have no choice but to accept that minor means forlorn, lost, just plain bad. Majors, we are conditioned to believe by triumphant moments in epic film and the problem-solving second halves of commercials, are just plain good.
There is notable difference in the quality of majors and minors, but this difference is not expressive. The expression has been chosen and assigned with resigned deliberation and repetition. Once it was accepted that minor meant sad, man had a tool. Every time this tool is used, the "meaning" of the chord is perpetuated. This incessant perpetuation has lead us awry in personifying an abstract object.
For comparison, let's examine a concept that is equally abstract and non-emotive in its natural state: the base 10 number system. The number 10 is no happier than the number 10,000. That is, until you assign a context. 10,000 JuJu Bees are certainly better than 10 of them. Unless you suffer from type-two diabetes, in which case the opposite is true.
If one were to adhere to the belief that in all cases, major means happy, it would mean that it would under no circumstances be appropriate to sing a sad lyric in a major progression.
Enter Wheatus, stage left.
These young men, each weighing less than 100 pounds soaking wet with boots on, sang, "Teenage Dirtbag." The song featured the chorus, "I'm just a teenage dirtbag, baby!" It's pathetic thought, the poor boy. But the line is sung in such a catchy, major progression, it's impossible to imagine him singing it with anything but a Joker smile slathered across his chops. The young man, in his less-than-profound lyricism, made a poignant musical statement of irony, challenging tradition.
It's feasible that if enough of these types of statements are made, we could have an Orwellian reversal of what is and always has been.
The emo group Midtown recently released an album called "Forget What You Know." Emo groups are, of course, known for their characteristically formulaic song structures and sappy lyrics to match. Midtown has chosen to stray from the formula. Contrasting with their typically emo song structures, they consistently refer to existentialism in their lyrics. Even if their songs are simple restatements of Jean-Paul Sartre's points and lines, they exemplify the point that the prose need not match the conventionally accepted tone of the coinciding music.



