Å·±¦ÓéÀÖ

“One way of emphasizing the singularity of the recent past is [..] to observe that the total number of humans ever to have lived is estimated at around (a bit less than) 100 billion. One of Walt Whitman's poems has a memorable image—thinking of all past people lined up in orderly columns behind those living—‘row upon row rise the phantoms behind usâ€�. Actually, looking over our shoulder, we would see only around 15 rows.”