||Modality (from Latin modus, â€˜measureâ€™, â€˜mannerâ€™, â€˜meansâ€™) is a key concept in philosophy and in music. In philosophy, it means having to do with necessity or possibility. Some truths and falsehoods are necessary. It is necessarily true that 2 + 2 = 4; that is, it could not have been false that 2 + 2 = 4. And it is necessarily false that 2 + 2 = 5; that is, it could not have been true that 2 + 2 = 5. (In contrast, some truths and falsehoods are merely contingent. It is merely contingently true that the dog is in its box; that is, it could not have been false that the dog is in its box. And it is merely contingently false that the dog is on the sofa; that is, it could have been true the dog is on the sofa.)
Philosophers have distinguished various forms of possibility and necessity. It is logically necessary that all bachelors are unmarried. That is, it follows from the laws of logic and the meanings of the words â€˜bachelorâ€™ and â€˜unmarriedâ€™ that there cannot be a married bachelor. It is not logically necessary that water be H2O. Simply by reflecting upon the meanings of the words â€˜waterâ€™ and â€˜H2Oâ€™, and the laws of logic, one cannot know that water is H2O, let alone that water is necessarily H2O. But, if Kripke\'s discussion of rigid designators is correct, it is impossible for water not to be H2O. There is no possible situation in which water is not H2O. So it is metaphysically impossible for water not to be H2O. That is, there is no possible situation in which water is not H2O, but this is not due to the meanings of words and the laws of logic alone.
It is not logically necessary that water boil at 100Â°C. Nor does this seem to be metaphysically necessary. It is possible that water should have a different boiling point but only if the laws of Nature are different. So long as the laws of Nature are as they actually are, then it is necessary that water boils at 100Â°C. It is nomologically necessary that water boils at 100Â°C. That is, in all possible situations in which the laws of Nature are as they actually are, then water boils at 100Â°C.
In medieval musical notation, modality originally referred to the various combinations of long and short note values, known as the â€˜rhythmic modesâ€™. But, more generally, modality in music is a concept involving musical scale and melody. It is important to distinguish between the terms â€˜scaleâ€™ and â€˜modeâ€™, which are often confused. Scale is simply a stepwise progression, ascending or descending, of single notes, whereas mode can be defined as a particular scale with its own special characteristics, or as a melodic model or type. To describe a piece of music as modal is to imply the presence of some hierarchy of musical tones and their relationships, or some distinguishing melodic patterns such as closing phrases or cadences. In other words modality is the way a scale is used in an individual melody. In musicology, the concept of mode as a type of scale is often used for the classification or grouping of monophonic melodies, particularly folk songs, into theoretical categories.
In Western music history, modality is also associated with the period ranging from early medieval liturgical chant to Renaissance polyphony. During this time, music was based on scale-type modes derived from ancient Greek musical theory. These modes, often inappropriately referred to as the â€˜churchâ€™ or â€˜ecclesiasticalâ€™ modes, are approximately equivalent to the seven scales that can be made using only the white notes of the piano.
In many Asian musical traditions mode may be interpreted as a melodic model or basis for composition and improvisation. In India, for example, a raga is a mode that is identified not only by its characteristic ascending and descending tone patterns and motifs, but also by the ornamentation, embellishment and degrees of emphasis associated with specific tones. These modal elements form the musical material with which a performer will improvise. Furthermore, each raga is related to a particular mood, sentiment, time of day, season and other extra-musical factors. These factors, known in advance from tradition, affect both the performers as they improvise on the raga and the listeners as they experience the music.
Modality is also a crucial element in melodic recognition. In Western music, the identity of a melody is determined by a unique and invariable succession of tones. However, in the art music of many Oriental traditions the same melody may exist in several different modes, and consequently may comprise several contrasting tone sequences. Its identity, therefore, is related more to its contour than to its precise tonal constituents.
Finally, in jazz terminology, â€˜modal jazzâ€™ refers to a style of improvisation that emerged during the late 1950s, and in which melodic improvisation, instead of being conditioned by conventional harmonic structures, is based on modal principles. AJ KMcL SSt
See also actuality; rigid and non-rigid designators; scale.Further reading S. Kripke, Naming and Necessity; , A. Plantinga, The Nature of Necessity.