Theory and analysis are in one sense reciprocals: if analysis opens up a musical structure or style to inspection, inventorying its components, identifying its connective forces, providing a description adequate to some live experience, then theory generalizes from such data, predicting what the analyst will find in other cases within a given structural or stylistic orbit, devising systems by which other works – as yet unwritten – might be generated. Conversely, if theory intuits how musical systems operate, then analysis furnishes feedback to such imaginative intuitions, rendering them more insightful. In this sense, they are like two hemispheres that fit together to form a globe (or cerebrum!), functioning deductively as investigation and abstraction, inductively as hypothesis and verification, and in practice forming a chain of alternating activities.

Professionally, on the other hand, “theory” now denotes a whole subdiscipline of the general field of musicology. Analysis often appears to be a subordinate category within the larger activity of theory. After all, there is theory that does not require analysis. Theorists may engage in building systems or formulating strategies for use by composers; and these almost by definition have no use for analysis. Others may conduct experimental research into the sound-materials of music or the cognitive processes of the human mind, to which analysis may be wholly inappropriate. And on the other hand, historians habitually use analysis as a tool for understanding the classes of compositions – repertories, “outputs,” “periods,” works, versions, sketches, and so forth – that they study.