Final answer:
The passage from Emerson's 'Nature' highlights the contrast in perception of nature between adults and children, indicating that children have a deeper, heartfelt connection to nature.
Step-by-step explanation:
The central idea of the passage from Ralph Waldo Emerson's essay Nature is the notion that adults and children perceive nature differently.
The key words that lead to this understanding are 'few adult persons can see', suggesting that adults have lost the ability to truly perceive the natural world, and 'the sun illuminates only the eye of the man, but shines into the eye and the heart of the child', emphasizing that children have a deeper, more heartfelt connection to nature.
Emerson contrasts a superficial worldly perception with the profound, intuitive insight of a child, arguing for a return to a more innocent and pure way of experiencing the world.