"Virtual reality is a fairly new concept to us; but once you grok it, it seems clear that any civilization that was capable of starflight and longevity extension, and so forth and so on, would also have a full VR toolkit under control. Well then, that means that when we go looking for the extraterrestrial, what will be the footprint? Perhaps vanished races are all around us, but downloaded into solid-state matrices that we have only recently come to the point where we could even recognize that possibility."