How Does Your Memory Work?

What is memory? In the seventeenth century, about 350 years before the development of brain imaging technology, the philosopher Thomas Hobbes wrote in his masterpiece Leviathan that "imagination and memory are but one thing." To think that imagining and remembering are the same thing may sound ridiculous, but modern science, as today's documentary reveals, is confirming Hobbes' intuition in strange ways: the brain activity patterns of memory, for instance, seems to be indistinguishable from the brain activity patterns of imagination, for roughly the same reasons Hobbes thought.

Also in the seventeenth century, philosopher John Locke advanced the astute notion that what makes you who you are is not your soul or spirit, but your consciousness and memory. Memory is, in other words, the criterion of personal identity. Ask yourself who or what you would be without your memories. How would you function? What could you learn? How would you make plans? What would be your own sense of self?

If memories and imagination really are indiscernible, how would you know when you are remembering something and when you are simply imagining it? How could you trust your own judgment?

More radically, if your memories really are what makes you who you are, as Locke thought, and memories are the same as imagination, what does this say about your self? Are you simply some character being imagined by yourself or someone else? Is the reality of you no different from something merely imagined? Is your past nothing more than some illusion your mind creates? Is there such a thing as your past?

If you want to learn more about the great mystery of memory, and how this mystery is finally starting to be unraveled, check out this great RadioLab episode, and if you want to learn about the strangest case of amnesia ever recorded, click here.
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