The Life of Psi

Philosophical Musings on the Foundations of Physics and Chemistry

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Have you always wondered whether Schrödinger's cat is alive or dead? Does the thought of higher dimensions and parallel universes blow your mind? Are you looking for the blueprints to build a time machine or a teleportation device? Are you puzzled by the puzzles of quantum mechanics, intrigued by the unidirectionality of the arrow of time? In that case, you've reached the perfect blog! Welcome!

Launched in September 2013, The Life of Psi is aimed at introducing non-experts to the foundations of physics and chemistry (although I hope experts will find something of interest here as well). The Life of Psi seeks to provide one-monthly posts on some of the fascinating, and often mind-boggling, topics from the borderland between philosophy and science, written in a clear and easy-to-understand way. The subject matter is always kept to a theoretical minimum and discussion via the comments section is greatly encouraged.


My worldline

Pieter Thyssen

My name is Pieter Thyssen (That's right, like the Thyssen elevators). Whereas my left brain was trained as a theoretical scientist, my right brain has always preferred the piano and music composition. At work, I either hunt for (broken) symmetries or dabble in the history and philosophy of science. Most of the time however, I get stuck in another dimension, contemplating time travel and parallel universes, or thinking about ways to save Schrödinger's cat (maybe). I explore the world on foot, and I take life one cup of (Ethiopian Arabica) coffee at a time. You can follow me on Twitter @PieterThyssen and reach me via email at

It's been more than ten years now since I first set foot on the science campus of the KU Leuven (Belgium) and began my studies of chemistry. As a student, I quickly discovered my fascination for the foundations of physics and chemistry, and (so far) that fascination has only grown. For the last decade or so, I was mostly involved in the history and philosophy of chemistry.

Pieter Thyssen 3

Perhaps not surprisingly then, my PhD research focussed on the symmetries, hidden in Mendeleev's periodic table of the elements. If all goes well, the results of these adventures in symmetry land — a daunting 600 pages — should appear in (OUP) book form towards the end of this summer. The title however is still a surprise — to me as well.

Recently, my interests have shifted more towards the philosophy of physics, and in December 2014, I started a second PhD in philosophy on the topic of time travel and backward causation — or to put it more scientifically — on the quantum mechanics of closed timelike curves and retrocausality.

Despite the impressive title, I remain a simple chemist. I didn't enjoy an all-embracing education in philosophy or theoretical physics, and the philosophy of physics is a relatively new field to me. But I'm thrilled to embark on this new adventure and I love spending my evenings with a cup of Arabica coffee, while reading books on the philosophy and foundations of physics — gradually filling in the holes in my knowledge.


The Life of Psi

This is how the idea for The Life of Psi was born. The idea is really very simple: As soon as I read about something new and interesting, I'll try to write it down in a post in as clear a way as possible such that non-experts, like me, could delve into the foundational wonderlands of modern science.

But I am especially interested in your thoughts, and I can only encourage you to join the conversation. By commenting on the posts, I hope lively discussions will ensue between experts and non-experts alike, pondering the very foundations of our science.

The various posts, due to appear on The Life of Psi, will cover topics as diverse as quantum nonlocality, quantum cryptography, the arrow of time, time travel, the philosophy of space and time, and the periodic system of chemical elements. Announcements of conferences and workshops on the foundations of physics and chemistry, as well as short book reviews will appear as well.


What's in a name?

Central to quantum mechanics is the so-called wave function, commonly denoted by the Greek letter psi (\psi). The wave function holds all the information about the quantum system under study; it provides us with the probabilities for measurement outcomes. That is, by making a certain measurement on the system, the wave function gets poked and (one is told) collapses onto one of the various possible outcomes with a probability dictated by the original wave function.

But besides being a useful calculation tool, physicists still wonder whether \psi is something really real? Lying at the root of all quantum mysteries, the wavefunction remains a key player in most scientific and philosophical debates on the interpretation of quantum mechanics. (As a case in point, a collection of essays on the metaphysics of quantum mechanics recently appeared with the appropriate title The Wave Function.)

This blog aims to study The Life of Psi (a word play on the fantasy adventure novel, The Life of Pi) by attempting to answer such questions as: How does Psi's life look like? That is, how does Psi evolve in time? In particular, what happens to Psi's life when it collapses upon measurement? And what is its ontological nature?


How to get in touch?

You can get in touch with The Life of Psi by sending an email to, or by following The Life of Psi on Twitter (@TheLifeofPsi). Alternatively, you can always reach me at, or follow me on Twitter (@PieterThyssen).

Don't hesitate to comment on the posts by leaving a reply at the bottom of the screen, and feel free to subscribe to by entering your email address below in order to receive notifications of new posts by email:

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  3 comments for “About

  1. fons
    June 28, 2016 at 2:46 pm

    Ik kan het allemaal niet volgen

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