This quote from Barbara W. Tuchman's "The Proud Tower: A Portrait of the World Before the War, 1890-1914" presents a sharp critique of someone's intelligence. It suggests that the individual is so lacking in intellect that even a slight increase in their mental capacity would still leave them below average, which speaks to the depths of their ignorance.

The phrase is both humorous and biting, indicating that the person in question might not be capable of understanding complex ideas or engaging thoughtfully with the world around them. Tuchman's work often examines the sociopolitical landscape of the early 20th century, and this quote reflects her keen observational skills regarding the folly and inability of certain figures in that era.