How much are we willing to lose from our already short lives by losing ourselves in our Blackberries, our iPhones, by not paying attention to the human being across from us who is talking with us, by being so lazy that we're not willing to process deeply?

Our culture is an edifice built of externalized memories.

It is forgetting, not remembering, that is the essence of what makes us human. To make sense of the world, we must filter it. "To think," Borges writes, "is to forget.

Since at least the Middle Ages, philosophers and philologists have dreamed of curing natural languages of their flaws by constructing entirely new idioms according to orderly, logical principles.

As bad as we are at remembering names and phone numbers and word-for-word instructions from our colleagues, we have really exceptional visual and spatial memories.

Our ability to find humor in the world, to make connections between previously unconnected notions, to create new ideas, to share in a common culture: All these essentially human acts depend on memory.

With our blogs and tweets, digital cameras, and unlimited-gigabyte e-mail archives, participation in the online culture now means creating a trail of always present, ever searchable, unforgetting external memories that only grows as one ages.