Final answer:
Defoe justifies his text by asserting that 'Robinson Crusoe,' while fictional, carries historical and allegorical truth, suitable for the common good, which is consistent with earlier narrative traditions yet innovative through its use of realism and moral instruction.
Step-by-step explanation:
The extract in question appears to be from the preface or a similar section of Daniel Defoe's novel Robinson Crusoe. Defoe is addressing criticisms that the story is entirely fictional and thus, not valuable. In response, he asserts that the story is allegorical and historical, thereby falling within the tradition of narrative writing while also contributing to it. The allegation of fiction is rebuffed as 'an Invention scandalous in Design, and false in Fact,' suggesting that Defoe sees a higher purpose in his work, intended 'for the common Good of Mankind.' This is aligned with the tradition of authors such as Chaucer and Boccaccio, who wrote allegorical works that were both entertaining and instructional.
Moreover, Defoe's claim of historical basis echoes the defense tactics used by the poets of antiquity, like those mentioned by Aristotle, who argue that their portrayals, while not always true-to-fact, reflect a higher truth or present things 'as they ought to be.' His work is also reminiscent of the narrative tradition that includes travel stories and adventure tales that were popularized by books such as 'The Travels of Marco Polo' and 'Le livre des merveilles' by John de Mandeville.
Defoe innovatively uses the realism associated with the Enlightenment's focus on science and facts while pioneering the English novel genre, showing how fiction can offer a critical perspective on real-world situations. In doing so, Defoe helped establish a new form of prose fiction that merges realistic storytelling with instructive themes, thus responding to the social and philosophical movements of his time.