Everything your saying is reasonable, but the whole thing (the logic, the experiences and memory) is happening in your mind. Just as it is with me. There's no way to prove an external reality. Maybe it exists, maybe it doesn't. It can't be proved because all we have is our subjective pereception. Your assertion that there is as objective, external reality is an assumtion which cannot be proven.
In a dream, you might make the same confident declaration - "yes there is a car here, and obviously it's real for everyone. Belief is irrelevant". The same level of confidence as you have now. And yet someone watching you dreaming might have a very different perception. There's no way to tell right now whether you're dreaming or not.
