The notion that the universe around us might be an elaborate illusion stems from knowledge's mediated nature. We perceive things not as they are in themselves, but as they appear to us through our senses and cognitive abilities. Experience has shown us that our senses and reasoning can sometimes deceive us. Even the most complex knowledge is built upon basic elements, and if these foundational elements are partly illusory, then everything built upon them could also be illusory, even if it seems coherent to us.
