In this quote, George Henry Lewes is highlighting the significance of insight in the production of art. He is suggesting that insight is the structure of art, and without it, art can not be developed. Insight is the capability to gain a deep understanding of something, and Lewes is recommending that this understanding is required for the creation of art. He is implying that art is not simply a physical act of producing something, however rather an act of understanding and analyzing the world around us. Insight is the capability to see beyond the surface area of things and to get a deeper understanding of the world. Lewes is recommending that this understanding is essential for the production of art, as it allows us to reveal our thoughts and sensations in a creative way. By having insight, we can develop art that is significant and has the prospective to move and inspire others.