“The attempts of brain damage victims to imagine falter thanks to an inability to marshal the places of the past.” (Scientific American) Bilateral damage to the hippocampus is known to cause amnesia. Now a study from the University of London found deficiencies in the abilities of five amnesiac men, compared with matched subjects, to imagine. It points to a greater role for the hippocampus in adding a temporal dimension to our experience; without its functions we exist in a timeless present. It makes a sort of sense that if you cannot have the experience of remembering a time gone by, you cannot imagine a time when the present moment will have passed. And one FmH reader [thanks, Joel] noted the resonance with T.S. Eliot:

And right action is freedom
From past and future also. (The Dry Salvages)