Motive and theme

Four notes are enough to recognise Beethoven's Fifth Symphony:

Hear the passage

Three short notes and a long one, a third lower. It is not a complete melody, it does not end on a cadence, and still it is unmistakable. It is a motive.

The motive

Med defines the motive as a brief musical figure, clear and precise in shape, made of a well-defined combination of intervals and rhythm, which makes it easy to remember. And he adds its purpose: the motive is a unifying element of the work, repeated many times in the course of the composition (Med 1996, ch. XLIX).

The two halves of the definition go together. The motive has to be short and sharp to be recognised when it returns; and it returns because that is how the work holds together. In the Fifth Symphony, the first thing Beethoven does with the four notes is repeat them a step lower:

Hear the passage

It is the same idea, shifted within the key. The falling third has changed from major to minor, and the ear recognises the motive all the same, because the rhythm and the shape stayed. All the techniques of melodic manipulation, sequence, inversion, augmentation, work on ideas of this size.

The rhythmic motive

A motive does not even need fixed pitches. Blatter shows that in "The Battle Hymn of the Republic", a nineteenth-century American song, one dotted rhythmic figure returns throughout the piece and is one of the things that unify it (Blatter 2007, part 5, art. 3). The notes change; the rhythm stays.

The same goes for Beethoven's four notes. What you hear through the first movement is often just the rhythm, short, short, short, long, on different pitches.

For Blatter, structuring a composition so that its parts share related material, in pitch, shape or rhythm, is the essence of composition (Blatter 2007, part 5, art. 3). The motive is the unit of that kinship.

The inciso

Med also defines the inciso, a small musical cell made of an impulse and a repose (Med 1996, ch. XLIX). The impulse is the note, or group of notes, that sets off; the repose is where it lands:

Hear the passage

Two incisos: the first rises and lands on C, the second circles C and lands on it again. The inciso is music's smallest breath, the smallest unit that already has a beginning and an end. Motives and incisos are, for Med, the smallest elements in the structure of a melody, below the phrase and the period (Med 1996, ch. XLIX).

The theme

At the other end is the theme, the fundamental idea of a work. Med defines it as a well-defined melody with significant musical content, and gives as examples the first and second themes of a sonata (Med 1996, ch. XLIX).

The difference from the motive is one of scale and role. The motive is a cell; the theme is a whole melody, usually with phrases and cadences, that the work presents as its main subject. A theme usually contains motives, and working on those motives is what lets the theme be developed: broken up, transformed, recombined.

A work can have several themes, and many forms live on the contrast between them. In a classical sonata the first and second themes are set against each other in character and in key. In a theme and variations, a single theme is presented and then transformed many times.

From cell to form

Motive, inciso, phrase, period, theme, form: these are levels of one construction, from smallest to largest. Blatter notes that when a form is represented with letters, the larger, bolder ones mark the broadest structures and the smaller ones the details, down to the motive (Blatter 2007, part 5, art. 4). Looking at a work up close is finding its motives; looking from afar is seeing its themes and sections.

What comes next

Between the motive and the theme lies the phrase, the unit that ends in a cadence, and the period, which joins two phrases as question and answer.