Tory Peterson, when he made the field guide for the birds, knew that you can’t carry a big book such as The Birds of Minnesota, two large volumes, in the field. No, he said, let’s see now. What would you see if this were a North American Flicker and he flew? What you would is see a yellow rump patch and no bird of that size in this area shows a yellow rump patch and red head and so forth. So what he was trying to do was identify the bird by indicating what you would see, what you would hear, how the flight would go if (you encountered) that bird. Now that’s a very good example of critical common sense of our ability to select from an infinity of detail what counts for dealing with the issue at hand.
John E. Smith in, Phillip McReynolds, The American Philosophers Interviews on The Meaning of life and Truth