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# physics posts

## Book Review: Time Loops

The book Time Loops by Eric Wargo makes a careful argument for the reality of precognitive dreams. My personal interest in this topic has to do with my obsession with time and to an extent, time travel. The author starts the book by summarizing a number of examples of dreams that came true, and closely studies an early dream pioneer named J.W. Dunne who wrote An Experiment with Time. What stands out about Dunne is how he made the distinction between dreaming about events out in the world vs events as experienced by the future self.

## Qubits and the Multiverse: how to 𝚐𝚒𝚝-𝚋𝚛𝚊𝚗𝚌𝚑 your life

Have you ever had a decision that was hard to make because both sides of the decision were great in their own way? Where you stress over the decision and wish you could split into two copies of yourself? Some decision theorists recommend flipping a coin, but there is a better way. Coins are made of lots of atoms, and many of those atoms are entangled with each other and with the environment.

## CWEB LaTeX Experiment

I have written about literate programming a few times before. The big idea is to elevate documentation above the actual running source code. Source code is meant for humans to read, that’s why it has higher-level abstractions and comments. Literate programming flips the roles of comments and source code. The comments come first, and the source code is stripped out and tangled into a compilable form. I am still not totally sure what to think about it.

## Time in Physics

In 1666, when the Plague was ripping through England, Isaac Newton went into quarantine outside the city and developed calculus. Calculus is an application of Euclid’s geometry to problems involving time. Geometry models space, calculus models space and time. The reason the ancient Greeks didn’t develop calculus is because of tools. The ancient Greeks had rulers and compasses but not reliable clocks. They used the rulers and compasses to do geometry, and discovered many eternal truths about space and shape.

## Conservation Confusion Clarified

Ported from my old blog through Archive.org (donate to Archive.org here!) I took a kinematics class last term, and I was surprised to learn from the textbook that the law of conservation of energy was an empirical fact and not a necessary result of something more general. This means that no one has ever found a counterexample to it. (All claims of perpetual motion have been debunked) After the term ended and I entered winter break I did what every reclusive antisocial nerd who doesn’t play video games does, I pursued my curiosity by reading alternate materials on the subject.