By emotion I mean the modifications of the body, whereby the active power of the said body is increased or diminished, aided or constrained, and also… - Benedictus de Spinoza

...We know at least since Spinoza that joy and its variant lead to a greater functional perfection, and that sorrow and related effects are unhealthy and should therefore be avoided. But music allows us to feel pain and pleasure simultaneously, both as players, and as listeners. [...] Music to me is sound with thought, and as Spinoza believed that rationality was the saving grace of the human being, then we must learn to look at music like this too.

...Spinoza became aware of this in a way that made him show his true colours (to the annoyance of his critics, who systematically attempt to misunderstand him on this point, Kuno Fischer, for example), when, one afternoon, rummaging around among who knows what memories, he turned his attention to the question of what actually remained for him, himself, of that famous morsus conscientiae - he who had relegated good and evil to man's imagination and angrily defended the honour of his 'free' God against the blasphemists who asserted that God operates everything sub ratione boni ('but that would mean that God is subject to fate and would really be the greatest of all absurdities' –). For Spinoza, the world had returned to that state of innocence in which it had lain before the invention of bad conscience: what had then become of morsus conscientiae?...

Even more, in the created thing, is a perfection that she exists; since the greatest of all imperfections is, not to exist.