What is music theory? It’s a tricky question to answer, because “music theory” has been and continues to be applied to all sorts of musical concepts and elements. But not all of it is actually music theory. For example, the statement “a whole note gets four beats” is an explanation of how to perform a whole note, but music theory is not needed to know how many beats to hold a whole note. That statement helps us understand how to perform a whole note, it does not explain how music or a specific piece of music, works in the physical realm. I realize that some who read this article may disagree with my premise. I will welcome your comments. Respectful, scholarly discourse is valuable, and I look forward to it. Now, before going further, we need to know what a theory is and what it does.

We probably know of many theories. The theory of relativity, the theory of evolution, quantum theory are just of few of them. All theories have one thing in common: they all are well-substantiated explanations of an aspect of the natural world. Theories can incorporate laws, hypotheses and facts, but these alone are not theories, they are merely supporting evidence of the theory. So the theory of gravitation, for instance, explains why apples fall from trees and astronauts float in space. 

The sounds we understand as music are also an aspect of the natural world. They are produced by sound sources that vibrate, creating sound waves of controllable frequency (pitch), amplitude (volume), timbre, and duration (rhythm). The field of science known as acoustics deals with these concepts. The ways in which musicians use these acoustical principles, is what music theory explains.

It’s important to understand that we don’t need music theory to have music or to create music. Before there ever was such as thing as music theory, people were already making music. There is evidence of the existence of flutes as early on as 7000 B.C. Egyptians were using harps, double-reeds, and lyres by 3500 B.C. So musical practice preceded music theory. The creation of music does not depend on music theory, nor are rules constructed by music theorists necessary to create music. It is always true that the music precedes the theory about that music. There can be no theory if the thing the theory is about does not exist. How could the theory be substantiated if what it explains cannot be observed? In other words, music is not created from theory, theory is created from music. Music theory explains what has already been done. Composers are aware of these things once they have become common practice. 

The ancient Greeks are recognized as producing the first music theorists, notably Pythagoras and Aristotle, and the period of time during which this occurred was between 700 and 480 B.C. So music had already been around thousands of years without any help from music theory. Further advances were finally found necessary almost 2,000 years later, in Europe during the Renaissance. 

So if music theory is not a set of instructions for writing music, and it’s not the “nuts and bolts” of music notation, then what is it? Music theory is an explanation of why music, both in general and in regard to specific works, sounds the way it sounds and effects us the way it does. Music theory is necessary to answer questions like, “why do the opening notes of Beethoven’s fifth symphony sound strong and driving instead of leisurely and soothing?” Why does the beginning of Morton Feldman’s String Quartet (1979) sound different from the beginning of Bartok’s String Quartet No. 4 in C major? Why does one sound calmer than the other? How does each work cause you to experience the feelings or emotions you do while you listen? There are physical properties of sound at work; things like timbre, resonance of overtones, dissonance and consonance. Which opening sounds more dissonant and why? In other words, our ears tell us what we are hearing, music theory explains why it sounds that way and has that effect on us. 

While knowing how to read music is a necessity for classical musicians, it is a convenience in the use of music theory to study music. If we can read the score, we can more easily discover why the music sounds and acts as it does. But we can discover the same things by just listening, though admittedly and frequently with considerably more difficulty and perhaps less specificity, depending on the complexity of the object of our study. But the notation is the set of instructions that tells the musicians how to produce the sounds that we want music theory to explain. Notation instructs the musicians to do specified things to set in motion, to manipulate, the physical properties of sound to accomplish a design made by the composer; a design that includes an expressive intent. What the music expresses is not the province of music theory, but why it expresses it is. Indeed, we rely on music theory to explain those active physical properties. “We use music theory to explain what’s going on when we hear sounds put together as music. …Music theory helps us understand why music is doing a particular thing, and it helps us predict what might happen next, too. …Finally, music theory dips into the realm of physical and psychological responses in listeners and how musicians and composers might use those predictable reactions to create even more dynamic and moving experiences.” (Is Music Theory A Science?, schoolofcomposition.com, accessed 3/9/23)

Meyer (Emotion and Meaning in Music, 1956) and Narmour (Musical Perception, 1991) both wrote extensively on the satisfaction and withholding of musical expectations. Both of these investigations represent works in the field of music theory. So does Langer’s Philosophy in a New Key. They offer explanations of how music works. Research into music cognition also falls within the realm of music theory. Examples are Lerdahl and Jackendoff’s A Generative Theory of Tonal Music, and Lerdahl’s Tonal Pitch Space. Of course, any treatise analyzing musical works are of music theory. 

Some courses offered by Music Theory departments are not really music theory. Ear training, for example, is not music theory. Students learn to sight sing and audiate music using sofege and other tools. They learn a skill, but there is nothing for a theory to explain in any of that instruction; no more than there is in learning how to play a tune on a clarinet, or an etude on a piano. Even while reading music, the activity of playing and reading music needs no further explanation, except that one might explain how the human brain is processing the notation and making those perceptions available for the nervous system to use to execute fingerings, breathing, articulation, and so forth. That is the realm of music cognition, which does require music theory. 

So, in summary, music theory explains why music sounds, acts, and effects the way it does, how our brains perceive and understand those sounds, and how creators of music take the physical properties of sound, and fashion them into musical works that bring artistry, pleasure, and more into our human lives.