The Gryphon in Alice's Adventures in Wonderland explains that lessons are called so because they lessen over time, implying that as we learn, the amount of ignorance decreases. This humorous observation highlights the idea that education helps diminish our lack of knowledge gradually.
It also suggests that learning is an ongoing process where understanding grows as we progress. The Gryphon's remark emphasizes the importance of continuous learning and the idea that each lesson learned slightly reduces our ignorance, making the journey of knowledge a decreasing one.