In his essay "The Skeptic," 18th-century English philosopher David Hume concludes:
In a word, human life is more governed by fortune than by reason; is to be regarded more as a dull pastime than as a serious occupation; and is more influenced by particular humour, than by general principles. Shall we engage ourselves in it with passion and anxiety? It is not worthy of so much concern. Shall we be indifferent about what happens? We lose all the pleasure of the game by our phlegm° and carelessness. While we are reasoning concerning life, life is gone; and death, though perhaps they receive him differently, yet treats alike the fool and the philosopher. To reduce life to exact rule and method, is commonly a painful, oft a fruitless occupation: And is it not also a proof, that we overvalue the prize for which we contend? Even to reason so carefully concerning it, and to fix with accuracy its just idea, would be overvaluing it, were it not that, to some tempers, this occupation is one of the most amusing, in which life could possibly be employed.
My question is about the use of the word "dull" in the first sentence (which I've boldfaced for easy reference). In context, it seems he doesn't mean "boring" as is the modern meaning of the word, as that contradicts the thrust of the paragraph. What was the historical meaning of the word that he is using here?