this thought might not be welcome in this thread but it does perhaps focus a little more on what we mean by the word 'purpose'.

Brother Quenon is a monk at Gethsemane Abbey which is where Thomas Merton the author was a monk for many years. In fact it was the writings of Merton that led him to go there 53 years ago. There is a short interview somewhere on youtube which I heard the other day in which someone asks him what is the purpose of a life in a monastery and he replies like this:
"Well, I think the purpose of the monastic life in the modern world is to show that we don't need a purpose. The purpose of life is life, and you are to be just to be. Everybody measures their importance by how useful they are, so you need to shatter that. You know, somebody has to come along now and then just say listen, you know, that's not it. That's not what life is."