Life seems to speed up as we get older because life gets less memorable as we get older.

Memory training is not just for the sake of performing party tricks; it's about nurturing something profoundly and essentially human.

What makes things memorable is that they are meaningful, significant, colorful.

If you were a medieval scholar reading a book, you knew that there was a reasonable likelihood you'd never see that particular text again, and so a high premium was placed on remembering what you read. You couldn't just pull a book off the shelf to consult it for a quote or an idea.

We're all just a bundle of habits shaped by our memories. And to the extent that we control our lives, we do so by gradually altering those habits, which is to say the networks of our memory. No lasting joke, or invention, or insight, or work of art was ever produced by an external memory. Not yet, at least.

To attain the rank of grand master of memory, you must be able to perform three seemingly superhuman feats. You have to memorize 1,000 digits in under an hour, the precise order of 10 shuffled decks of playing cards in the same amount of time, and one shuffled deck in less than two minutes. There are 36 grand masters of memory in the world.

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.