I used to think hope and optimism were the same thing. But, more recently I've come to the conclusion that I cannot be both hopeful and optimistic about something at the same time. Hope is defined in many ways, as is optimism. To me, hope is an emotion, not based on any facts or knowledge, just a desire or wish. Optimism suggests knowledge of or an awareness of the potential of things working out - an expectation.
It's easier to understand the difference in context. For example, about the state of the world; lets see...given human nature, politics, greed, inequality and environmental degradation, I don't expect things to work out well in the long run, nor in the short run. I am not optimistic. However, I am hopeful. I hope that future generations will be wiser, that technology will help, that the world will become more equal, that racial and gender discrimination will decrease. I cannot believe, based on my knowledge of the world, that anything will improve or have the potential to improve. I cannot imagine how things will change. I can only hope that things will change.
I'm glad to be aware of the difference now. It's helped me to organize and categorize some of my thought and musings. When I'm bitter or fed up about something, such as the craziness in the world like the recent assassination of Bhutto, I can reflect both intellectually and emotionally. I can be angry and hopeful at the same time, discouraged and determined, enraged and energized. It's good to know that I am not becoming consumed by anger and disappointment, which was my previous belief and fear. I have hope to cling to and that's better than nothing.