We try to understand our surroundings and inner feelings through knowledge, but we have an unobservable barrier to our surroundings or even our inner selves. We have no access to the surroundings. All our knowledge about the "surroundings" comes from our senses. We have phenomena but no access to the thing that creates the experiences. For more than 2500 years of epistemology, [[The Historircal overview of the phenomenological cage|nobody had found a reliable way to establish a relationship between perception and the “surrounding”]]. To demonstrate the problem of the relations between knowledge and the surroundings, we may use the thought experiment of the “[http://en.wikipedia.org/wiki/Brain_in_a_vat brain in a vat].” In this thought experiment, you are asked to find a reliable way to know if you exist as you perceive it or if you are a brain in a vat, which gets its sensory inputs from a computer that simulates the perceived world. As a result of our inability to go beyond our perceptions, I will call this principle '"The phenomenological cage principle'''.

===Axioms of Knowledge===