This is an interesting way to think, ever see The Matrix? Reality is how we perceive it, I have always said. Some people agree, others don't. My definition of reality may not be "ultimate truth", but rather it is the truths that I can grab and get a hold of with my comprehension of what I can perceive as being real. Two people can be standing next to each other and have completely different realizations of a situation, there by making each individuals realities different in their mind. So what matters to you, the reality as you perceive it, or "ultimate truth"? I would assume "ultimate truth", but I am afraid that there are too many times, as you might agree, "ultimate truth" to you is just reality how you perceive it, to others.