in Thoreau’s Journal:

Access to nature for original observation is secured by one ticket—by one kind of expense—but access to the works of your predecessors by a very different kind of expense- All things tend to cherish the originality of the original. Nature at least takes no pains to introduce him to the works of his predecessors-but only presents him with her own Opera Omnia.

Is it the lover of nature who has access to all that has been written on the subject of his favorite studies? No; he lives far away from this. It is the lover of books & systems-who know nature chiefly at 2nd hand.