Category Archives: Science

Quantum Sleeping Beauty and the Multiverse

Hidden in my papers with Chip Sebens on Everettian quantum mechanics is a simple solution to a fun philosophical problem with potential implications for cosmology: the quantum version of the Sleeping Beauty Problem. It’s a classic example of self-locating uncertainty: … Continue reading

Posted in Philosophy, Science | 106 Comments

Why Probability in Quantum Mechanics is Given by the Wave Function Squared

One of the most profound and mysterious principles in all of physics is the Born Rule, named after Max Born. In quantum mechanics, particles don’t have classical properties like “position” or “momentum”; rather, there is a wave function that assigns … Continue reading

Posted in arxiv, Philosophy, Science | 79 Comments

Galaxies That Are Too Big To Fail, But Fail Anyway

Dark matter exists, but there is still a lot we don’t know about it. Presumably it’s some kind of particle, but we don’t know how massive it is, what forces it interacts with, or how it was produced. On the … Continue reading

Posted in arxiv, Science | 22 Comments

Why the Many-Worlds Formulation of Quantum Mechanics Is Probably Correct

I have often talked about the Many-Worlds or Everett approach to quantum mechanics — here’s an explanatory video, an excerpt from From Eternity to Here, and slides from a talk. But I don’t think I’ve ever explained as persuasively as … Continue reading

Posted in Philosophy, Science | 237 Comments

Quantum Mechanics Open Course from MIT

Kids today don’t know how good they have it. Back when I was learning quantum mechanics, the process involved steps like “going to lectures.” Not only did that require physical movement from the comfort of one’s home to dilapidated lecture … Continue reading

Posted in Science | 16 Comments

Physicists Should Stop Saying Silly Things about Philosophy

The last few years have seen a number of prominent scientists step up to microphones and belittle the value of philosophy. Stephen Hawking, Lawrence Krauss, and Neil deGrasse Tyson are well-known examples. To redress the balance a bit, philosopher of … Continue reading

Posted in Philosophy, Science | 225 Comments

Quantum Mechanics In Your Face

(Title shamelessly stolen from Sidney Coleman.) I’m back after a bit of insane traveling, looking forward to resuming regular blogging next week. Someone has to weigh in about BICEP, right? In the meantime, here’s a video to keep you occupied: … Continue reading

Posted in Science | 14 Comments

Quantum Mechanics Smackdown

Greetings from the Big Apple, where the World Science Festival got off to a swinging start with the announcement of the Kavli Prize winners. The local favorite will of course be the Astrophysics prize, which was awarded to Alan Guth, … Continue reading

Posted in Philosophy, Science | 53 Comments

Arrrgh Rumors

Today’s hot issue in my favorite corners of the internet (at least, besides “What’s up with Solange?”) is the possibility that the BICEP2 discovery of the signature of gravitational waves in the CMB might not be right after all. At … Continue reading

Posted in Science, Science and the Media | 22 Comments

Squelching Boltzmann Brains (And Maybe Eternal Inflation)

There’s no question that quantum fluctuations play a crucial role in modern cosmology, as the recent BICEP2 observations have reminded us. According to inflation, all of the structures we see in the universe, from galaxies up to superclusters and beyond, … Continue reading

Posted in arxiv, Science, Time | 67 Comments