The mistake the writer¹ makes is to have sought wisdom for the sake of recognition, or for some other personal gain. In that sense it is indeed vanity (in our modern sense of the word). To seek wisdom for one's own ends most certainly will create a sense of emptiness. If wisdom and the accruing of knowledge is considered to be a burden, a possession to raise one's status, then an uneducated man may well be happier than the educated one—most certainly lighter. Acquiring wisdom for its own sake is a way of seeking God, becoming closer to the divine. When our motive is pure there is no vanity, and it is not purposeless or useless. Intent is what matters—motive. This passage has me asking myself what my motive is when I read a book, attend a workshop, engage in a debate. Am I truly seeking to learn, to become enlightened, or am I seeking an improved status, to be seen as smart among my peers? In truth, there is much of this latter intent. My motive is sometimes vain and impure, which is something to take stock of.

¹ The author of Ecclesiastes is thought to be an otherwise Biblically unmentioned man named Qohelet, possibly writing between 600 and 400 BC, and not King Solomon as often supposed.