  Be this as it may, the main point of Mendelssohn’s distinction is that because its signs are arbitrary and can therefore be associated with any conceivable content, “the poet can express everything of which our soul can have a clear concept,” while the arts that employ natural signs are limited to the expression of those ideas and emotions the natural signs for which can be replicated in their specific media; each of these arts “must content itself with that portion of natural signs that it can express by means of the senses,” or more precisely by means of its particular way of engaging the senses. For example, “Music, the expression of which takes place by means of inarticulate sounds,” although it can express both the general ideas of harmony and all of the particular “inclinations and passions of the human soul which tend to make themselves known by means of sounds,” cannot possibly indicate particular concepts of objects such as “the concept of a rose, a poplar tree, and so on, just as it is impossible for painting to represent a musical chord to us” (“Main Principles”; Philosophical Writings, pp. 178–9). A similar point would be made a century later by the music critic Eduard Hanslick.