In order to become aesthetically active the arts of the muses or the ‘music’ arts have to be performed. A work of art, though composed, practised, or written down beforehand, only comes to life in the execution of it, that is, by being represented or produced in the literal sense of the word – brought before a public. The ‘music’ arts are action and are enjoyed as such every time that action is repeated in the performance. The case is quite different with the plastic arts. The very fact of their being bound to matter and to the limitations of form inherent in it, is enough to forbid them absolutely free play and deny them that flight into the ethereal spaces open to music and poetry. In this respect dancing is in an anomalous position. It is musical and plastic at once: music since rhythm and movement are its chief elements, plastic because inevitably bound to matter. Its execution depends on the human body with its limited manoeuvrability, and its beauty is that of the moving body itself. Dancing is a plastic creation like sculpture, but for a moment only.