What seems rational and honest is based more on your prejudices than anything else. Ultimately, who and what you choose to believe is up to you. If you choose to restrict yourself to only what can verified without assumptions, you will end up with solipsism. If you choose to believe everything that comes your way, you will end up very confused. If you find some arbitrary 'halfway' heuristic, then you'll probably be better off. Just never forget that it is a heuristic that you are using as a criterion, or else your belief will be just as arbitrary as those who wait for alien spaceships to take them to bliss.

Really, its arbitrary. Just make up your mind.