Play only the white keys from D to D and you hear the Dorian mode
Start on D, play every white piano key up to the next D, and you have the modern Dorian mode: a minor-sounding scale with one surprisingly bright note. That raised sixth gives Miles Davis's So What its cool, and it links Gregorian chant to Santana. Oddly, the ancient Greek Dorian was a different scale entirely.
The name comes from the Dorian Greeks, but their Dorian harmonia, in its diatonic form, matched what we now call the Phrygian pattern, the white keys from E to E, with slightly different tuning. It was built from two four-note segments separated by a whole tone, and Greek theory even had versions using quarter tones. The label then wandered. The theorist Ptolemy in the 2nd century borrowed it for one of his seven transposition keys, Boethius passed that meaning into Latin, and 9th-century chant theorists reassigned the old Greek names once more, until a commentary called the Nova expositio turned them into a set of eight scales. The resulting medieval system drew on the Byzantine church's eight modes, creating the false impression that Byzantium had inherited them straight from Greece.
Medieval singers treated Dorian flexibly. B flat was allowed by licence alongside B natural, typically natural going up and flat coming down, and C was often sharpened to lead into the final D. A lower-lying version of the same pattern was called Hypodorian.
The modern Dorian is stricter. Measured against a major scale, its third and seventh steps are flattened while everything else, including the sixth, stays put. Put another way, it is a major scale played from its second note, or natural minor with the sixth raised. Its pattern of whole and half steps reads the same upwards and downwards, making it symmetrical. The composer Balakirev called it Russian minor, and Hindustani and Carnatic music have their own equivalents, Kafi and Kharaharapriya.
The sound runs through centuries. The chant Dies irae is Dorian, and Saint-Saens used the mode in Carnival of the Animals to suggest a Persian atmosphere. In jazz, both So What and Herbie Hancock's Maiden Voyage set their main sections in D Dorian and shift up a half step for the bridge. Tears for Fears' Mad World lands on a chord that carries the telltale major sixth.
Source: Dorian mode
