What sense does that make? I believe that I will wake up tomorrow morning. I do not know that this is the case (inevitably, it must fail to be so eventually), but I believe it's so nonetheless. As a consequence of that belief, I think and act in all respects as if it were true.
Nothing requires me, nor anyone "rationalist" or otherwise, to be free from such a belief.
That doesn't change the fact that the belief isn't rational.
It may not even be the correct word to use in relation to the example you give here.
You do not know (who does) that you will wake up tomorrow morning.
But...
...what
reason would you have to
believe that you will wake up tomorrow morning?
You either will or you won't. Since that is the case, under normal rational circumstances, there is not need to
believe.
If someone were to ask me if I would still be
alive in the morning, the logical rational answer would be "I don't know".
(you are talking about dying in your sleep right? Or are you saying that you might not wake in the morning but at a later time in the day?)
Whatever the case,
Belief - especially in the context of the thread topic - has nothing to do with your argument above.
Lets suppose that your argument is talking about assumption. Assumption can mean:
presume, suppose, take it, take for granted, take as read, take it as given, presuppose, conjecture, surmise, conclude, come to the conclusion, deduce, infer, draw the inference, reckon, reason, guess, imagine, think, fancy, suspect, expect, accept, believe, be of the opinion, understand, be given to understand, gather, glean;
But none of those are
rational in relation to your argument above.
Belief is irrational.
You either WILL awake tomorrow morning or you will NOT awake tomorrow morning.
(If you are speaking about dying in your sleep you either WILL awake tomorrow morning or you will be dead.)
You have no reason to bring belief into it...no rational reason anyway.
And that is the context of this thread topic. "To believe or not to believe? (is that the question?) to be asking.
ETA:
When I go to sleep at night, I have no thoughts (ordinarily) on whether I will wake up or die in my sleep. On the odd time I do think about that question, I simply *shrug* and think to myself "Who knows! I certainly don't and there's no use losing sleep over it!."
That to me is the logical, rational way to think about the question.
Belief is irrational.