"Yes," Dr. Malone went on, "they know we're here. They answer back. And here goes the crazy part: you can't see them unless you expect to. Unless you put your mind in a certain state. You have to be confident and relaxed at the same time. You have to be capable--Where's that quotation ..." She reached into the muddle of papers on her desk and found a scrap on which someone had written with a green pen. She read: ' "... Capable of being in uncertainties, mysteries, doubts, without any irritable reaching after fact and reason.' You have to get into that state of mind. That's from the poet Keats, by the way."