“Life is a journey to be experienced, not a problem to be solved, take a deep breath.”

Source: Vampire Academy

Source: Silverthorn

Source: The Road Less Traveled: A New Psychology of Love, Traditional Values, and Spiritual Growth

Source: Big Stone Gap

Attributed to Merton in a number of sources, the earliest located being Studia mystica, Volumes 5-6 (1982), p. 76 http://books.google.com/books?id=59EYAAAAIAAJ&q=%22problem+to+be+solved%22#search_anchor. This does not attribute a direct quote to Merton, but says "To use another of Merton's favorite distinctions, for Furlong Merton's life is seen principally as a problem to be solved, which it was, in the final analysis, successfully, rather than a mystery to be lived". The next-earliest source located is the 1998 book The Artist's Way at Work: Riding the Dragon by Mark Bryan and Julia Cameron, which attributes the exact quote to Merton on p. 152 http://books.google.com/books?id=CghAQDPahhcC&lpg=PP1&pg=PA152#v=onepage&q&f=false. In reality this seems to be a slightly altered version of the quote "The mystery of life is not a problem to be solved; it is a reality to be experienced" which appeared in the 1928 book The Conquest of Illusion by Jacobus Johannes Leeuw, p. 9 http://books.google.com/books?id=OFdVAAAAMAAJ&q=%22not+a+problem+to+be+solved%22#search_anchor.
Misattributed

Bowdoin Academic Spotlight interview (2011)
Context: You have to take advantage of the opportunities that life gives you, particularly the moments in time when you have time, when you're between jobs or you retire. Get out and go. I think most of us are way too intense. We need to take a deep breath and do things that maybe don't fit the normal picture of what we're supposed to do at that stage of life. In some ways, this book is one big argument for just plain loosening up.

"The Big Problem Binge," The New York Times (1965-03-18)

Source: 1970s and later, From Utopian Theory to Practical Applications, 1970, p. 10