Leonardo compares unwilling study with eating against one’s appetite. In both cases, something that can normally be beneficial becomes less useful when it is undertaken without readiness or interest. Applied to learning, the comparison suggests that simply receiving information is not enough for it to become lasting knowledge.

The emphasis is on the relationship between interest, attention and memory. When a learner approaches a subject without curiosity or engagement, information may be encountered but not properly absorbed or retained. Leonardo therefore presents learning as an active process in which the state of mind of the learner matters alongside the material being studied.

The passage can be applied to education and independent study as a reminder that effective learning often depends on finding purpose in a subject. It does not suggest avoiding difficult material, but rather cultivating sufficient interest and attention for study to become meaningful and memorable.