Part of a continuing effort to fight the idea of "Dark Ages" by extending the Renaissance back further and further rather than just pointing out that the Dark Ages were a flawed and propagandistic concept to begin with? (See also: Carolingian Renaissance of the 9th century)
Ok. From Aristotle until the mid-12th century, is 15 centuries, during which Western thought stagnated in the natural sciences. Clearly, there was some kind of Dark Ages or great decline, or else a great long stagnation, between the height of classical Greek philosophy and the Scientific Revolution. The 12th century is as good a point as any to mark when the stagnation began to end, but if you propose a different date that is fine. But to say there is no Dark Ages, leaves the question of why there was such a long stagnation in the natural sciences after Greek philosophy.
Except this revival of Greek and Latin and traditional culture led to a stagnation of the vibrant culture of the High Middle Ages? While brilliant early humanists like Petrarch managed to use classical knowledge to complement the existing language, later humanists would insist on a straitjacket imposition of the style of Cicero etc. on the Latin language, strangling one of the most vibrant languages of knowledge by forcing it to conform to first century writing styles, and killed it by turning it into a museum piece? The way art and architecture abandoned flourishing Byzantine and Gothic styles and embraced the tyrannical boredom of domes, pediments, and columns? The outflow of Greek literature was never "lost" (Aquinas was quite familiar with Aristotle well before the Renaissance) and was the inspiration for many of the brilliant philosophers of the Medieval era from Avicenna to Averrones, and the Ottomans, especially, had many, many, many experts on the classics on hand well before the "Renaissance."
The cultural and artistic life of the Middle Ages gets totally short shrift because people with contempt for monasticism and the Church ignore their vibrant intellectual culture in this period and focus on their Renaissance heroes (many of whom were employed by aforementioned Church, from the book hunters to the artists). Similarly, the continued presence and relevance of Greek literature in Islamic Spain and Anatolia (and responses to those Arabic works throughout all of Latin Christendom) is inconvenient to notions of seeing Europe as an isolated entity when it was part of a vast system stretching thousands of miles eastwards (see all the Chinese knowledge the Mongols bring west, including gunpowder, not to mention the safe overland trade routes).
