Menu Close
A cat, or the superposition of an inordinate number of wave functions? Blind Hen ⁑ Blind Höna

Schrödinger’s Qur’an – a 2012 thought experiment

Whenever I see angry mobs reacting to the destruction of religious books it makes me think of Schrödinger, iPads and how we should interpret fundamentalist religious teachings in the digital era.

The brilliant Austrian physicist Erwin Schrödinger won the 1933 Nobel Prize for Physics for his contributions to quantum theory.

He is best known for his 1935 “thought experiment” in which a (perhaps otherwise cute and loveable!) pussycat is placed in a sealed and sound-proof box along with a radioactive isotope that has a 50% chance of decaying by the time the box is finally opened.

If the isotope decays before the box is opened, it triggers a minor explosion that ultimately leads to the release of a deadly gas and the cat will be dead when the box is opened.

If it doesn’t decay the cat will be alive and in need of a cuddle! The genius behind this thought experiment was two-fold:

Firstly, the experiment linked quantum theory (the rules of physics that apparently accurately describe the behaviour of microscopic particles) to the macroscopic world with which we are all familiar.

Quantum mechanics demanded that the atomic isotope could not be thought of as either decayed or intact, but rather as the superposition of two wave functions, that mutually exist until the observer makes an observation and forces the isotope into one state or the other when the box is opened.

Since the cat is nothing but the superposition of an inordinate number of wave functions, with each of its sub-atomic particles all in quantum states, then according to quantum mechanics it too must be subject to the same physical laws as the single atom.

Thus while in the box the cat is neither dead nor alive but in a combination of the two states until the “observer” forces it into a solitary one by opening the box.

Now our “common-sense” view of this thought experiment is that this is ridiculous! How can the cat be half-dead and half-alive?

And yet most undergraduate (and indeed senior) physicists who are passionate “believers” in the quantum theory, would advocate that the cat is truly neither dead nor alive, but half-dead and half-alive until the box is opened, at which time the wave function collapses and the cat is “forced into a state”. Fantastic!

Fox & Thomas

The second act of genius was to use an object that tugs at our heartstrings (the cute daredevil pussycat) to highlight our humanist – as opposed to the quantum mechanical – view of the universe and common sense.

Our emotional connection to the cat transforms the problem out of the mathematical world into our everyday one and adds a bit of spice to nerdy physicists’ otherwise mundane lives. For a physicist, this is about as good as it gets!

Quantum theory was championed by the “Copenhagen School” of physicists and Schrödinger created the paradox to demonstrate its apparent absurdity when applied to macroscopic bodies, such as cats.

The 2012 version of the Paradox

Now if Schrödinger was not a 1930s Austrian genius, atheist and practitioner of open-marriage principles, but instead a rather conventional Australian astrophysicist and technology junkie in 2012 looking to explain the above paradox to readers of The Conversation, he might substitute the pussycat for a copy of the Bible or Qur’an – objects that, if deliberately destroyed, could lead to great passion, even riots and death.


In this (I stress) 2012 thought experiment (kids, do not try this one at home, nor in some provinces of Afghanistan or Southern states of the US) he could announce that he had built a sealed container with an iPad containing a digital version of the Holy Book connected to a radioactive isotope that, if decayed, would lead to the digital erasure of the manuscript half the time when the container was opened.

In the non-Copenhagen view, angry mobs would potentially take to the streets if, when the box was finally opened, the iPad no longer contained the Holy Book.

But half the time the Holy Book would be intact, and the mobs could disassemble when the box was opened and go back to their daily lives as no act of desecration would have taken place.

However, in the Copenhagen (quantum mechanical) view, the mob shouldn’t wait for the first anniversary opening, as the minute the box was closed, the holy book would become progressively more and more destroyed as time progressed.

Quantum mechanics-educated religious leaders might explain to their followers that their anger should build gradually with time, and then either evaporate or lead to a riot when the box was finally opened.

In the true quantum-mechanical tradition, a physicist could extend this thought experiment to write a php script that would randomly download one of the Bible, Qur’an or even a classical quantum mechanics textbook to the iPad first.

Without revealing which text was downloaded, the iPad could then be sealed and this fact announced to the world.


Now firebrand Christian preachers could form a strange alliance with their Islamic counterparts, and even devotees of the quantum theory, all waiting in horror to see if their sacred books were destroyed, albeit digitally.

This leads to a fascinating problem for the potential mobs that might ultimately assemble and be affected!

When the box is opened and the iPad powered on, it will either reveal an intact Bible, Qur’an or Classic Quantum Mechanics textbook, or half the time nothing.

In the non-Copenhagen or “humanist” view, the mob will never riot, as the physicists, and people of different religions, will all either see their books safe and sound, or not know whether their competing religions have had their digital texts deleted or their own, making the excuse for a riot impossible.

The thought experiment’s quantum mechanically educated mobs however will oscillate between being very angry and rejoicing until the box is opened; at which point they’ll either be in an eternal quandary, not knowing which book was destroyed, or happy that it still exists.

Curiously, this thought experiment is actually happening every day.

The flash memories present in iPads suffer random interactions with high energy cosmic rays that can randomly render their contents destroyed, and the Bible and Qur’an are present on many of them.

Fortunately, this doesn’t lead to riots, although I still wonder if dragging a holy book to the “trash” is the digital equivalent of burning it?

P.S. No cats, holy books of any description, or iPads were harmed in the preparation of this piece.

Want to write?

Write an article and join a growing community of more than 184,200 academics and researchers from 4,969 institutions.

Register now