ARTS, Liberal, or Seven Liberal. The distinction between the liberal arts and the practical arts on the one hand, and philosophy on the other, originates in Greek education and philosophy. In the Republic (Bk. xi.) of Plato, and the Politics (viii. 1) of Aristotle, the ‘liberal arts’ are those subjects that are suitable for the development of intellectual and moral excellence, as distinguished from those that are merely useful or practical. The distinction was always made, by the Greek theorists, between music, literature in the form of grammar and rhetoric, and the mathematical studies, and that higher aspect of the liberal discipline termed philosophy. Philosophy was sometimes called the liberal art par excellence.
Daniel Coit Gilman et al. et. (1905) The New International Encyclopædia, lemma "Arts, Liberal"