Down the Rabbit Hole

Quantum theory is usually presented as a challenge to classical physics. In fact, it challenges a much older physics, the “intuitive” or “folk” physics we all learned as infants. Our first step toward understanding quantum theory is understanding our intuitions about the physical world, where they come from, and what function they serve in our psychology and hence in our lives. We’ll see how these intuitions seeped into the classical physics of Galileo and Newton, and from there into quantum theory itself. We will discover a deep contradiction between our earliest intuitions about the physical world and the theories — classical and then quantum physics — we have built to describe it.

Duration: 1 hours, 30 minutes

“Quantum” means discrete. A “quantum” number is a number we can write down, like one or 100 or 2.34. We will trace the origin of the “the quantum” in physics and find that it comes from the requirement for *answers we can write down*. All of physics is about answers we can write down, so all of physics, even “classical” physics, is quantum. We will then think about what it means to ask a question and get an answer we can write down. Quantum theory will start to emerge – beginning with Heisenberg’s uncertainty principle and moving on to superposition and entanglement – as we think about this process. We will also encounter surprising connections to the psychology of perception and to the fundamental idea of “computation.”

Duration: 1 hours, 30 minutes

Once we see that quantum theory is about observation, it becomes clear that it is also about memory. Memories must be recorded — “written down” — even in our heads. We must then “read” what we have written down if we want to use the information we have recorded in our memories. Now we come face-to-face with the contradiction we discovered in Session 1: we cannot, without contradicting ourselves, do physics and treat our memories as sacrosanct. The growing evidence that cognition is quantum suddenly makes sense. But we are now in freefall: without the touchstone of memory, our certainty about identity — for the objects around us but also for ourselves as observers — evaporates.

Duration: 1 hours, 30 minutes

Quantum theory is simple and seemingly inevitable. It has survived every test we have been able to devise. But what are we to make of its lessons? It tells us, very clearly, that the world does not consist of separate things with which we can separately interact. Our distinctions of one part of the world from another have no physical significance, it tells us, and no effect on the world’s behavior. But if they are not separate, individual things, what are other people, let alone the other objects around us? Quantum theory does not even let us privilege our own memories as separate and separately accessible. What then becomes of the personal histories we so strongly believe in? What becomes of our identities?

Duration: 1 hours, 30 minutes