Joseph Wood Krutch, The Forgotten Peninsula: A Naturalist in Baja California
(New York: William Sloane Associates, 1961), p. 201:
Your amateur, on the other hand, is delightfully if perhaps almost sinfully free of responsibility and can spread himself as thin as he likes over the vast field of nature. There are few places not covered with concrete or trod into dust where he does not find something to look at. Best of all, perhaps, is the fact that he feels no pressing obligation to "add something to the sum of human knowledge." He is quite satisfied when he adds something to his knowledge. And if he keeps his field wide enough he will remain so ignorant that may do exactly that at intervals very gratifyingly short. A professional field botanist, for instance, has done very well if in the course of a lifetime he adds a dozen new species to the flora of the region he is studying. Even a hitherto unrecognized variety is enough to make a red-letter day. But to the amateur, any flower he has never seen is a new species as far as he is concerned and on a short trip into a new area he can easily find a dozen "new species."