If you don’t know what intellectual depth means, you’ll think it means thoroughness. But thoroughness is not depth, it is density within a given breadth and depth of knowledge.

Both excessive breadth of knowledge (how many things one has knowledge of) and excessive density of knowledge (how much one knows about a thing) will be gained at the expense of depth of knowledge (how many ways one knows how to know). And alas, vice versa. Dilettantes, pedants and nomads.