Barzun on William James

I am reading some of Jacque Barzun on understanding and reading William James. I found this passage rather unique:

[The real problem] in James as writer of philosophy is his irrepressible humour. He shares with Swift, Lamb, Samuel Butler, Shaw, Chesterton, and Mark Twain the disadvantage of having used yet one more rhetorical means which, though legitimate in itself and generally pleasing, somehow distracts all but the fittest readers. Most people seize on it as an opportunity to escape from the serious thought just preceding and thus miss the seriousness in the next, the humorous one. The great humorist always runs the risk of not being taken thoughtfully, while the normal men of ideas, faithful to solemnity, invariably are.