Why Marshall McLuhan thinks every medium is an extension of the human body?

Marshall McLuhan believed that media act as extensions of our senses and capabilities, shaping how we perceive and interact with the world. He argued that each medium, whether it be the written Word or television, extends a different aspect of our consciousness, essentially becoming part of our sensory apparatus. McLuhan's view highlights how media technologies influence our understanding and experience of the world, much like how our physical body does.