People often complain that music is too ambiguous, that what they should think when they hear it is so unclear, whereas everyone understands words. With me, it is exactly the opposite, and not only with regard to an entire speech but also with individual words. These, too, seem to me so ambiguous, so vague, so easily misunderstood in comparison to genuine music, which fills the soul with a thousand things better than words. The thoughts which are expressed to me by music that I love are not too indefinite to be put into words, but on the contrary, too definite.
~Felix Mendelssohn in a letter to Marc-André Souchay, October 15, 1842
For I consider that music is, by its very nature, essentially powerless to express anything at all, whether a feeling, an attitude of mind, a psychological mood, a phenomenon of nature, etc....Expression has never been an inherent property of music. That is by no means the purpose of its existence. If, as is nearly always the case, music appears to express something, this is only an illusion and not a reality. It is simply an additional attribute which, by tacit and inveterate agreement, we have lent it, thrust upon it, as a label, a convention - in short, an aspect unconsciously or by force of habit, we have come to confuse with its essential being.
~Igor Stravinsky (1936). An Autobiography, p.53-54.