Some researches pointed out that this number of his articles were too small even though they were written in the same period when he was writing "Gakumon no susume" and "Bunmeiron no gairyaku" (An Outline of a Theory of Civilization).
この点につき『学問のすすめ』や『文明論之概略』の執筆時期と重なるとはいえ、少なすぎると指摘する研究もある（戸沢1991）。