Perhaps the only reason humans percieve water as being tasteless is because it is constantly present in our mouths, in the form of saliva. Most biological processes, such as digestion, for example, take place unconsciously (meaning that we are unaware as it occurs). Since saliva is always present in the mouth, perhaps humans have built a sort of immunity to it, making it one less process that requires concentration. So, the question is, really, CAN WE TRUST OUR PERCEPTIONS?!?! I'm going to bed now.