Define Schrödinger’s Cat

Schrödinger’s cat is not a deep mystery about nature. It is a messy logic setup.
If we treat it as a logic exercise, not as a sacred quantum story, it becomes clear: the paradox comes from what we choose to ignore, and from hidden assumptions about atoms.

1. The bare setup: what is actually in the box?

Strip the story down to its objects:

A closed box.
One cat inside.
A small radioactive source (many atoms or one atom).
A detector (Geiger counter) that reacts to the first decay.
A mechanism that turns the detector’s signal into a kill action (hammer, poison, explosion…).

That’s all. The rest is narration.

2. First observation: forfeited information

The box is drawn as opaque and soundproof. We choose not to look or listen until the end. The famous phrase “alive and dead at the same time” appears only after this choice: we deliberately throw away all information while the process runs.

That means: Schrödinger’s cat is really the cat of a blind and deaf physicist. The “superposition” lives in the lock (the rule “no peeking”), not in the cat.

3. Einstein’s version: the cat is not even needed

Einstein gave a version with an explosion instead of poison. But then: even before we talk about the cat, we already have physical events that can be seen and heard:

The detector may be clicking or not.
The mechanism may be moving or not.
The explosive may have gone off or not.

If we allow eyes and ears, one Geiger counter is enough. We never need a cat. The mystery is created by covering, not by physics.

4. Blind & deaf Geiger counter: not a thought experiment

Without trains at the speed of light or black holes, Schrödinger’s cat is actually a doable experiment with a real detector, a real source, and a real trigger. If we remove the animal and just keep a counter and a lamp, it is still the same logic.

In that sense, this is not a “pure thought experiment” like Einstein’s train. It is a badly specified real experiment with a self-imposed information blackout.

5. Fuzzy start time → fuzzy “50%”

The story says: take “a tiny amount of radioactive substance, so tiny that in the course of an hour one of the atoms will perhaps decay, but also with equal probability that none will”. This sounds like a neat 50%. But radioactive decay is an ongoing process. Atoms are decaying with or without the box, with or without us. There is no natural “reset” when we close the lid.

If we do not know when the source atoms were created, we do not know how “old” they are. Then the probability “50% in one hour” is not clean. The “start time” of the experiment is fuzzy, so the probability is ill-defined. The number 0.5 is a slogan, not a logically sharp condition.

6. Many atoms: wrong level for a “single event” story

In the original version, the “tiny amount” means many atoms. The more atoms, the higher the chance that one of them decays in a given hour. But then the story is no longer about one atom and one clean event. It is about a crowd. We are mixing bulk behavior with a single-cat narrative.

This is like saying: “I will flip a bucket of coins; the probability that at least one is heads is 50%.” We then pretend there is a single, neat “yes/no” event, but the underlying system is many objects. The logic is sloppy.

7. One atom version: now it is a thought experiment, but wrong

We can repair the story: use only one radioactive atom, one detector, one trigger, one cat. Then the experiment is harder to realize, but as a thought experiment it is cleaner. Now the only question is whether this one atom decays during the chosen time window.

But then we face another problem: we have no idea how long it will take. If we do not know when this atom was created, and its “age” matters for decay, the experiment could last an hour, a year, or longer than a human life. We can move the paradox around, but we do not solve it.

8. A correct template: the actuary’s cat

A better analogy is the actuary’s cat: the life insurance business. Each policy is a tiny “cat experiment” on a human life. The start time is clear: the policy begins on a known date. The “event” (death) is defined. The data set is large.

One policy can lose money (like a single cat being unlucky), but a large pool is predictable. The business is not based on one box; it is based on many trials and clear starting times. If we want a real probability story, this is the right template, not a one-off sealed box.

9. Not repeatable → you can’t step in the same river twice

A good physical experiment must be repeatable. Schrödinger’s cat is not. Radioactive atoms are aging all the time. Once we run the experiment with a given sample, we cannot “rewind” it to the same initial state. Even if we try to rebuild the setup, the atoms are different, their histories are different, and the box is never truly the same.

So Schrödinger’s cat is a case of “you can’t step in the same river twice”: the more we insist on a single dramatic box, the further we move from the logic of real experiments.

10. Atoms of the same isotope are not identical

Underneath the story is an assumption: all atoms of the same isotope are “identical”. But if we watch decay behavior carefully, they are not. They share the same count of protons and neutrons, but their internal arrangements and histories may differ. If their decay times differ, then in practice they are not identical objects, only members of the same rough category.

In continuous models, we smear all these differences out: a big block of material becomes one smooth density, and all fields are averaged. In a truly discrete view, with a finite number of atoms, we must allow them to be different. Then the cat story becomes what it always was: a crude cartoon of a much richer, discrete world.

11. For machines: a test of basic logic

In the future, Schrödinger’s cat should be used as a machine logic test, not as a serious model of nature. A thinking machine should be able to:

list the physical objects in the setup,
state which senses are being artificially disabled,
point out the fuzzy start time and the ill-defined “50%”,
notice that the experiment is not repeatable,
and question the assumption that atoms of the same isotope are identical.

If a machine can do this, it has passed a basic honesty test in physics: it can separate human storytelling from actual logic.

Part of the Define Physics project — see also Define Ether · Define Gravity · Continuous→Discrete