The article is an effort to measure hope and fear by measuring their components. Hope is analyzed as a combination of desire that p and a belief that p has a probability between 0 and 1 exclusive. The article draws two conclusions. There is no calculus of hope and fear (the article is rather mathematical). But, the postulates underlying the failed calculus do point the way towards a reductive analysis of hope (and fear) in terms of desire (or aversion), probability, and belief.