I wouldn't characterise possibly threefold population growth over two centuries (or perhaps a doubling from the Ming peak) as an episode of stagnation or still less of decline. While an enthusiastic malthusian might consider such quantitative growth a fool's errand - and the increase was from an abnormal low following the turmoil of the 17th century - it nevertheless illustrates official success in supporting a substantial degree of material wellbeing after a time of upheaval, as efficient agricultural technique was promoted and state granaries extended (though an early "grow more rice" drive failed in unsuitable regions).

After an initial dalliance with western knowledge the dynasty does seem to have favoured Confucian tradition over experimentation, seeking to embed new enquiry into a classical scholarly framework. Elman (Cambridge history of China, v 9) notes state encouragement of new academies but also the late 18th-century controversy over "Han learning" vs "Song learning" which saw the ascendancy of the nominally older school but also a renewed emphasis on the natural sciences.

And after the catastrophes of the middle decades of the 19th century the regime showed itself not entirely closed to notions of modernisation, though the "self-strengthening" of the 1860s-70s and the administrative reforms of the 1900s ultimately proved a case of "too little, too late" in the face of mounting international challenges and domestic discontent. Overall, the picture is mixed and the dynasty's eventual fate tells its own story, but to rate the Qing a blanket failure seems to overlook the great expansion of the period, for all its lack of spectacular innovation.