David Deutsch interview in New Scientist

…is here. Great stuff.

One of the themes, which I totally agree with, is that quantum computation helps frame the whole “interpretations of quantum mechanics” boondoggle in a useful way. This topic was touched on also by Dave Bacon a few weeks ago.

Deutsch’s point of view, which I share, is that accepting quantum mechanics to be an objective description of reality logically implies the many-worlds picture.

This is the way I have always thought about quantum mechanics, and I certainly don’t have any problem, technical, philosophical or otherwise, with the objective reality of the variety of possible worlds. When we operate one of our machines, I always think of 2^16 (or however many qubits) universes, all with everything identical except the values of the 16 bits on the chip, all having objective reality. I am OK with the idea that my history most likely tracks through the universe with the correct answer if I set up my machine language correctly.

What I don’t get is why physicists, and specifically those that use quantum mechanics regularly, have a problem with the reality of the many-worlds implications of QM. It’s certainly the case that advances in science often reveal that things aren’t always what they seem, and that fundamental truths don’t have to be obvious. We are clearly extremely limited in our perceptive capabilities…why should we be confused or distressed if it turns out it’s hard for us to “pierce the veil” and see things as they are? And why should we be surprised if the true nature of things doesn’t always match our 5-sense grounded expectations?

4 thoughts on “David Deutsch interview in New Scientist

  1. When we operate one of our machines, I always think of 2^16 (or however many qubits) universes, all with everything identical except the values of the 16 bits on the chip, all having objective reality.

    But many-worlds must be saying something more than this, right? I mean, if your computer is sitting there in the computational basis state with all zeros, then we could also say that it is in a superposition of 2^16 states, just not the computational basis states. So unless you want to choose a fixed basis, then many-worlds doesn’t just need the existence of something like 2^16 worlds, but instead the existence of all 2^16 worlds compatible with the state!

  2. I have used HOL to prove that time is an illusion, all that has been or will be always was, and that complex adaptive systems invariably build to perception in a very small subset of quantum states possible in existence, said perceptive side effects of large scale continuity also known as “reality” as we “sense” it.

    Unfortunately the formal proof so generated is too long to fit into this message box…

  3. Dave: This is a good point! In our systems, there definitely is a fixed basis–the readouts are designed to measure only in this basis (call it Z). Even more that this, the readouts are designed to be used only when the qubits have settled into z-eigenstates. This selection of a preferred basis is one of the central concepts in our approach. So for these chips, all histories evolve through some 16-bit number produced by the readouts when they fire, and the 2^16 many worlds picture seems right.

    Is this relevant to the more general question you’re asking? I think it is…maybe this tracks back to the question of whether or not ultimately all histories track through events with fixed measurement bases.

  4. I am very happy I found this site. I read Deutsch’s book six or seven years ago, and many-worlds just makes so much more sense than anything else. It blows me away to see folks going through contortions to try to explain it away.

    Even funnier are the scientists who say you just can’t even think about what is going on in their black boxes. Ha ha.

    And I thought I was going to have to wait decades to see a computer with more than a few qubits.

    I think you must have neanderthal admixture, btw.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s