The Boltzmann Brains

In 1971, astronomer Frank Hohl built a computer simulation of the Milky Way. To his surprise, the simulation predicted disaster. The pretty spiral arms collapsed, and the orderly orbits of the stars became a chaotic mess. But wait - there's no sign anywhere that spiral galaxies are actually in trouble. Hohl’s simulation must have overlooked something - something invisible - that keeps everythi...

Does your favorite scientific theory introduce something that fills the entire universe but is otherwise invisible and intangible? Better think twice! In this episode, we talk about moments in history where scientists changed their mind about something huge. First up: outer space is filled with a clockwork machinery that carries the stars and planets around in their orbits. The catch: the clockwor...

Will every scientific theory eventually stumble on an unexplainable fact? If so, what does that mean for how we think about science? Sam tells Eric about a group of philosophers ready to throw the baby (i.e. science) out with the bathwater (i.e. these occasional errors). This idea is called "pessimistic induction". Eric, a scientist, does not love this idea. He and Sam put pessimism thro...

You spend your whole life devoted to the science of geology; teach generations of students; publish textbooks ... then, a German meteorologist with no training in geology gives a talk that says everything you know about the earth is WRONG. What would you do? In 1912, this actually happened, and geologists did NOT react well. This is the second part of our discussion of Alfred Wegener and his theor...

Eric wanted to talk about the discovery of continental drift in 1911, but the deeper he dug the more he realized he would need to cover a much older mystery first. In 1738, a team of Spanish and French explorers tried to measure the gravitational attraction of the largest mountain in Central America. It's a big lump of matter, so according to Newton it MUST exert a gravitational pull on everyt...

Gregor Mendel (1822-1884) founded the science of heredity with a series of famous experiments cross-breeding pea plants. And yet... when modern statistical techniques are applied to Mendel's original data, the agreement with theory is much too good. After his death, one biologist described him as either a miracle-worker or a liar. In this episode we'll talk about the lasting controversy su...

How can biologists do a controlled experiment when even genetic clones aren't identical? How can they compare plants in two labs when those labs use different soil and different lighting? Sometimes these sorts of things don't matter, and sometimes they mean your experiment is worthless! How do you know which is which?? Is there any hope for biology? Eric is a physicist who spent the last 2...

The universe we can see is big … really big. But what if it’s just a tiny piece of something way, way, way bigger? In this episode, Eric teaches Sam about the evidence for this bizarre possibility. If we can’t even see 99 percent of the universe, how can we know it’s there? Can science really draw useful conclusions about something we can’t observe now and won’t be able to observe in the future? S...

In this episode Sam takes the lead to discuss two of his favorite "paradoxes" from probability. The Monty Hall problem is a much-discussed challenge concerning the best strategy to win a car on a game show. The Sleeping Beauty problem describes a situation philosophers can’t seem to agree about, even today. Got a topic you’d like to hear us talk about? You can email us at theBbrains@gmai...

In this episode Sam and Eric discuss the evidence that our universe began about 14 billion years ago in a very hot, dense state, then gradually expanded and cooled. As late as 1920, Einstein thought this idea was obviously nonsense. Fifty years later, it was rock-solid science. Is the Big Bang Theory testable? After all, we can't grow a universe in a lab. How can scientists do their job in a s...

In middle school, most of us were taught the "scientific method" – a simplified list of steps meant to help kids understand how scientists approach the world. But how accurate is it, really? In this episode, we get to talking about the history of science, and discuss how the reality of scientific research stacks up against the famous "method". First, we discuss Galileo - the fi...

In this episode, Eric starts us off with an oldie but a goodie: In a Star Trek episode from 1989, Commander Data (an android) is put on trial by the Federation for refusing to be disassembled. Is Data just a man-made appliance, or is he a new kind of intelligent life, entitled to the right of self-determination? Next, Sam lays out some philosophical background on the twin questions of consciousnes...

BBrains pod: Is Philosophy Useful? Hi all! We’re Sam and Eric - the Boltzmann Brains. Sam is a philosopher, so of course he thinks philosophy is super-useful. But Eric has seen philosophers drift into irrelevance more than once, so maybe not? We're going to argue it out.  At least, that was the plan, until Sam immediately agreed that philosophy had some pretty profound limits. So, why pursue p...

Hi all! We’re Sam and Eric - the Boltzmann Brains. Today we’re doing dueling TV shows! Sam is a philosopher who loves The Good Place. Eric is a physicist who loves The Big Bang Theory. We’re going to discuss whether these shows look anything like reality. We’ll give both shows a grade (we used to be professors, after all), and along the way we’ll address such pressing questions as: Is moral philos...