Final answer:
The statement is true; Aristotle's 'Poetics' insists that a tragedy must maintain a comprehensible whole, with an appropriate length that allows the audience to easily remember and grasp the narrative's unity.
Step-by-step explanation:
For Aristotle, one of the measures of the appropriate length of a tragedy is one where the comprehensibility of the whole is maintained at all times. This statement is true according to Aristotle's Poetics, which emphasizes that a tragedy must be of a certain magnitude that allows the sequence of events to be easily embraced by the memory of the audience. The plot should conform to a structure that has a beginning, middle, and end, and should not exceed a length that would make it difficult for the audience to understand the unity and sense of the whole. This magnitude is crucial because it affects the beauty, and ultimately, the effectiveness of the tragedy in evoking the intended emotional response from the audience.
Furthermore, Aristotle discusses the importance of maintaining a balance between size and perspicuity in the narrative structure of tragedies. He notes that, much like an organism or object, both a very small size (which may be confusing and too quick to perceive) and a vast one (where the unity is lost due to overwhelming detail) are not ideal for the beauty of a tragedy. Hence, he sets the notion that the perfect magnitude of a tragedy is one that allows for an easily comprehendible change in fortune, which can be grasped in a single sitting without losing perspective of the whole narrative.