**2.1. Perception theories**

Theories of knowledge rely on psychological philosophy. As humans are surrounded by elements and patterns, they interact physically with them, but once these factors affect human behavior, this means people have started to perceive them. As the perception is variable, theories have the purpose of clarifying and shaping the phenomena. Perception could be direct naïve realism or the active process of representative realism. They could be based on human cognition idealism or even as a matter of abstract existence phenomenalism. Theories as philosophic concepts exist and are clear in their entire setting. Based on the perception theories, designing interiors have a set of standards as individual personality, cognition, values, education, and group cultures, professional ethics, faiths and beliefs. Therefore, by clarifying these theories, we will reach the basics of perceiving the beauty of an interior [4–6].
