hope is an embrace of the unknown

Hope is an embrace of the unknown and the unknowable, an alternative to the ceratinty of both optimists and pessimists. Optimists think it will all be fine without our invovement; pessimists take the opposite position; both excuse themselves from acting. It's the belief that what we do matters even tough how and when it may matter, who and what it may impact, are not things we can know beforehand. We may not, in fact, know them afterward either, but they matter all the same, and history is full of people whose influence was most powerful after they were gone. 

- Hope in th Dark (Foreword to the 2015 edition), Rebecca Solnit