Our culture is an edifice built of externalized memories.

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.

Monotony collapses time; novelty unfolds it. You can exercise daily and eat healthily and live a long life, while experiencing a short one. If you spend your life sitting in a cubicle and passing papers, one day is bound to blend unmemorably into the next - and disappear.

If you want to make information stick, it's best to learn it, go away from it for a while, come back to it later, leave it behind again, and once again return to it - to engage with it deeply across time. Our memories naturally degrade, but each time you return to a memory, you reactivate its neural network and help to lock it in.

To the extent that experience is the sum of our memories and wisdom the sum of experience, having a better memory would mean knowing not only more about the world, but also more about myself.

Once I'd reached the point where I could squirrel away more than 30 digits a minute in memory palaces, I still only sporadically used the techniques to memorize the phone numbers of people I actually wanted to call. I found it was just too simple to punch them into my cell phone.

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.