An interval denotes the difference in pitch between two sounds, measured as a frequency ratio or in cents, a logarithmic unit. In music theory, it describes horizontal (melodic) or vertical (harmonic) relationships, with characteristics such as major, minor, or perfect defining its nature.
Philosophers and scientists, from Galileo to Russell, examined intervals as temporal or spatial gaps, while authors like Marcus Aurelius portrayed life itself as a transient span. Whether in acoustics, mathematics, or metaphysics, the concept connects physical measurement with abstract perception, highlighting its universal significance across disciplines.