The sensed presence is some-times described as a "guardian angel" that appears in extreme and unusual environments.14 Particularly in life-and-death struggles for survival in these exceptionally harsh climes, or under unusual strain or stress, the brain apparently conjures up help for physical guidance or moral support. The descriptive phrase third man comes from T. S. Eliot's poem "The Waste Land":
Who is the third who always walks beside you? When I count, there are only you and I together. But when I look ahead up the white road There is always another one walking beside you Gliding wrapt in a brown mantle, hooded.
In his footnotes to these lines, Eliot explained that they "were stimulated by the account of one of the Antarctic expeditions (I forget which, but I think one of Shackleton's): it was related that the party of explorers, at the extremity of their strength, had the constant delusion that there was one more member than could actually be counted." In fact, in Sir Ernest Henry Shackleton's account it was a fourth man who accompanied the remaining three in the party: "It seemed to me often that we imwere four, not three." No matter, whether it is a third man, fourth man, angel, alien, or extra man, it is the sensed presence that interests us here because this is yet another example of the brain's capacity for agenticity; I shall refer to such companions as sensed presences and the process as the sensed-presence effect. In his book The Third Man Factor, John Geiger lists the conditions that are associated with the generation of a sensed presence: monotony, darkness, barren landscapes, isolation, cold, injury, dehydration, hunger, fatigue, and fear.' To this list we can add sleep deprivation, which probably accounts for Charles Lindbergh's sensed presence during his trans-atlantic flight to Paris. During the historic journey, Lindbergh became aware that he had company in the cockpit of the Spirit of St. Louis: "The fuselage behind me becomes filled with ghostly presences—vaguely out-lined forms, transparent, moving, riding weightless with me in the plane. I feel no surprise at their coming. There's no suddenness to their appearance." Most critically, these were not aberrations of the cockpit environment such as fog or reflected light because, as Lindbergh recounts, "Without turning my head, I see them as clearly as though in my normal field of vision." Lindbergh even heard "voices that spoke with authority and clearness," yet after the flight reported, "I can't remember a single word they said." What were these phantom beings doing there? They were there to help, "conversing and advising on my flight, discussing problems of my navigation, reassuring me, giving me messages of importance unat-tainable in ordinary life."