280 - David Albert & Jacob Barandes: Debating the Foundation of Quantum Mechanics

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**David Albert** (0:31)
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**David Albert** (1:00)
Think of the old Bertrand Russell skeptical scenario, where you say, for all we know, the world might have started only five minutes ago, in the physical condition that we took it to be in five minutes ago, and we would have no way of telling the difference. If Jacob's theory were true, we would have a way. This is a way of making vivid how novel this proposal is and how different it is from other fundamental physical theories that we've entertained in the past.

**Robinson Erhardt** (1:40)
This has been a long time coming. We're hot off of the release of my discussion with Jacob and Tim about Jacob's approach to quantum mechanics. And David, I know before we started, you wanted to make some introductory remarks about your perception of the invisibility approach. So I just wanted to give you the opportunity to start with that.

**David Albert** (2:04)
Sure.
Let me start by saying a little bit about what I'm going to do over the next 30 minutes or so.
For 30 years or so now, those of us who've been trying to make old-fashioned realistic literal sense of the foundations of quantum mechanics have been struggling mightily with the question of what to make of the quantum mechanical wave function. The trouble in a nutshell is that the wave function is a fantastically high-dimensional object and that the business of admitting such objects into the inventory of the fundamental physical furniture of the universe would seem to require that the fundamental physical space in which the history of the world plays itself out is fantastically high-dimensional as well, and that in turn raises a subtle and difficult question about how it is that that high-dimensional space might contrive to appear to us to have only three dimensions that we take, only the three dimensions that we take ourselves to move around in, in our everyday experience of the world. And what I'm going to be talking about here is a new picture of quantum mechanics, a picture that proposes to simply do away with wave functions, which is originally due to Jacob Barandes, who's here with us today, too.
And I'm going to approach that picture here as an attempt at understanding quantum mechanics as an exact and complete and literal and realistic account of the microscopic inner workings of the universe as a whole.
And I should note, and we'll see if this is out of date by now or not, because Jacob has told me about some recent developments, I should note that Professor, that Jacob himself, if I understand him correctly, is suspicious for a variety of reasons about the very idea of an exact or literal or complete scientific description of the universe as a whole. And these suspicions seem to play an important role, at least in the discussions I've had with Jacob some months ago. They seem to play an important role in shaping what Jacob is inclined to expect and in limiting what Jacob is inclined to demand of a satisfactory proposal for a fundamental physical theory. I'm not going to discuss those suspicions here. That would take us much too far afield, except to record that I don't share those suspicions myself. But I want to be clear at the outset that I'm going to treat Jacob's picture of quantum mechanics here for whatever it may turn out to be worth, and however he himself may have intended it, as an attempt at making straightforward, old-fashioned, flat-footed metaphysical sense of quantum mechanics, in the manner of, say, Bohmian mechanics or of the GRW theory or of the many worlds interpretation of quantum mechanics. And in particular, I'm going to be holding it to the same standards of clarity and exactness and universality as I'm accustomed to demanding of those other proposals.