I am simply following Occam's Razor, a principle created to solve problems. It essentially states that between two principles that hold up equally well, the one with the least assumptions should be considered more correct. We don't know anything to be completely true. There are an infinite amount of possibilities in the universe. There is the possibility that I am a figment of your subconscious mind. There is another possibility that I am a computer program. Therefore, we should hold nothing to be true. In that case, we should trust the 'reality' with the least assumptions. The more we base our theories on reality on our observations, the more they should be trusted. If we [i]assume [/i]something to be true, it is not backed up by evidence, but can be equally logically sound.