Do I think that the sun will rise tomorrow?
Do I believe that the sun will rise tomorrow?
Should I believe that the sun will rise tomorrow?
Does it matter whether I believe it or not?
Suppose I know that I am close to death, unlikely to last the night.
Then, for me, the sun will not rise tomorrow.
I may therefore take the view that I do not care.
But if I have family & loved ones, or responsibilities to others who have every reason to believe that the sun will indeed rise, for them, tomorrow, then I may have some duty to arrange my affairs as if I believe that too.
Or at least to say my goodbyes & thank yous.