The phrase "pious hope" refers to a sincere and faithful wish or desire. It often implies a strong belief or trust in something positive or good happening, particularly in the context of religious or moral beliefs. Full definition
Sam Harris said it well: «It is time we realized that to presume knowledge where one has only pious hope is a species of evil.» (religion.blogs.cnn.com)
«I think it is very sad that you believe it is acceptable to pretend to know things that you can not know — to think that is how you live your life is messed up to say the least — I hope you realize that to presume knowledge where one has only pious hope is a species of evil.» (religion.blogs.cnn.com)
They may still harbour the pious hope that young people will be attracted by matey liturgy and jolly tunes. (faith.org.uk)