Melanie McDonagh is surely right (“I do, therefore I am”, 9 May) in arguing that we do not bring about change in ourselves by thinking but by doing. She write that “this new thinking on thought and action” is a “very Catholic take on the world”. I am sure this is true, but it’s not entirely new thinking. Trying to remember where I had heard it before, I took down my copy of Hamlet (first published in 1603, 30 years before Descartes wrote his Discourse on Method) and read the following: “Assume a virtue if you have it not … For use almost can change the stamp of nature …”Is it more evidence that Shakespeare was a closet Catholic? Perhaps not, but it seems that Melanie McDonagh’s notion of “virtue as a habit&rdq