It seems to me, then, that Gorgias is right that tragedy is essentially the emotional experience of its audience. Whatever it tells us about the world is conveyed by means of these emotions. Plato agreed with Gorgias in this, but he disapproved of the process and regarded it has harmful. Aristotle agreed with him to, but, contrary to Plato, regarded it as beneficial and salutary. Plato's objection was that such emotions are not the province of the highest part of the soul, the intelectual part. This is the forefather of the error made by so many later critics who have acknowledged the centrality of emotion in the communication of tragedy. They think that if tragedy is essentially an emotional experience, it must be solely that: and they think this because they assume that strong emotion is necessarily in opposition to thought, that the psychic activities are mutually exclusive. But is this right? Understanding, reason, learning, moral discrimination; these things are not, in my experience, incompatible with emotion (nor presumably in the experience of Gorgias and Aristotle): what is incompatible is cold insensibility. Wether or not emotion is inimical to such intellectual processes depends on the circumstances in which it aroused.
Oliver Taplin, "Emotion and Meaning in Greek Tragedy", Oxfords Readings in Greek Tragedy, Erich Segal (ed.), Oxford University Press, s.d.