How much lies in Laughter: the cipher-key, wherewith we decipher the whole man! Some men wear an everlasting barren simper; in the smile of others lies a cold glitter as of ice: the fewest are able to laugh, what can be called laughing, but only sniff and titter and snigger from the throat outwards; or at best, produce some whiffling husky cachinnation, as if they were laughing through wool: of none such comes good. The man who cannot laugh is not only fit for treasons, stratagems, and spoils; but his whole life is already a treason and a stratagem.

Thomas Carlyle (1795-1881) Scottish essayist and historian

Sartor Resartus, Book 1, ch. 4 (1834)
    (Source)

This chapter first appeared in Fraser's Magazine for Town and Country, Vol. 8, No. 47 (1883-11).

"Treasons, stratagems, and spoils" comes from Shakespeare, The Merchant of Venice, Act 5, sc. 1, l. 92ff, where it's used to describe "the man that hath no music in himself."