In this poem, the enthusiastic speaker extols the virtues of nature's ability to educate humankind, and he implores his friend -- this friend might even be the reader him or herself! -- to put down his books and come outside to learn from the best teacher: Nature. He says,
Books! 'tis a dull and endless strife:
Come, hear the woodland linnet,
How sweet his music! on my life,
There's more of wisdom in it.
The speaker claims that books go on and on, dully, and for what seems like forever. One can read one book after another after another and still not really have learned anything of value -- nothing truly wise -- from one's endeavors. Wisdom, instead, is to be learned from nature, from listening to the linnet's song, for example. There is more wisdom to be found in those natural experiences than in any book. In this vein, the speaker continues, saying,
Come forth into the light of things,
Let Nature be your teacher.
He implies that one remains in both a literal and figurative darkness when one stays inside and gets one's education by reading alone. By going outside to learn from nature, one quite literally steps into the light, but one also steps into the figurative light of truth and wisdom. The education one gains from nature is far more illuminating, so to speak, than the education one gains from books. In fact, he claims that our book-learning may actually harm the beauty of the world around us, that it
Mis-shapes the beauteous forms of things: --
We murder to dissect.
Thus, he claims that, in our quest to understand and know, we have to kill our subject. To dissect it, to take it apart in order to understand it, we must actually murder it first. Surely this kind of education is not preferable, and it would be far better to allow our subjects to live, to experience true wisdom and actual truth, rather than to kill the thing we seek to know.