Schrödinger's Cat: Explained in Simple Terms

When people first hear about “Schrödinger's Cat,” they have many questions: “Is this a real experiment? Why talk about a cat and a box in physics? Can a cat be both alive and dead at the same time?”

In this article, we will delve into this famous thought experiment, why it is so important in quantum physics, and how this idea can be useful in everyday life.

About the author and the essence of the experiment

The main figure in the story is Erwin Schrödinger, an Austrian physicist and one of the founders of quantum mechanics. In 1935, he devised an imaginary scenario involving a cat in a box to demonstrate the oddity of quantum laws when applied to large objects instead of tiny particles.

So, imagine this:

1. There is an opaque box with a living cat inside.
2. The box contains a radioactive source with a 50% chance of decay (meaning it may or may not activate within a certain time).
3. A detector that senses the decay triggers a mechanism: if the decay occurs, a vial of poison is broken, and the cat dies. If there is no decay, the cat survives.
4. The box is closed, and no one can look inside.

According to quantum mechanics (if we take it “literally”), the cat inside the box exists in a “suspended state” — both alive and dead — until we open the lid and look. It sounds absurd, but this is exactly the paradox: when it comes to microscopic particles, such “superposition” (two states at once) is normal. But applying this to a cat seems too strange.

Why can the cat be both alive and dead?

In quantum physics, there is a concept of superposition. It’s when a particle (e.g., an electron) can exist in multiple states simultaneously until we measure where and in what form it is. But a cat is not a microscopic particle, right? In fact, Schrödinger's idea is built on this contrast: he wanted to show how illogical it seems to apply quantum laws to large objects from our everyday life.

While the box is closed, we don’t know whether the mechanism has activated or not. From the perspective of quantum mechanics, there is a probability that the cat is alive and a probability that it is dead. Until we actually look inside, theoretically, the cat “exists” in both states. But once we open the box, we immediately see a single state (the cat is either definitely alive or definitely dead).

What is the paradox?

In the ordinary world, things either happen or they don’t. A cat can’t be “half-alive.” But in the quantum world, things that seem impossible — like a particle being in two places at once — happen all the time. “Schrödinger's Cat paradox” reminds us that quantum effects don’t always fit the logic of our everyday experience.

Scientists have different explanations for why we don’t see such “weirdness” around us:

• The Copenhagen interpretation says: “The system definitively ‘chooses’ one state at the moment of observation.”
• The many-worlds interpretation suggests that all possibilities occur in parallel universes. In one universe, the cat is alive, and in another, it is not.
• Decoherence indicates that interaction with the environment “erases” quantum effects, turning them into events familiar to us.

You don’t need to delve into the details — what’s important is to understand that Schrödinger's Cat was created to show that quantum physics behaves very differently from how we are used to thinking about reality.

What does it teach us?

At first glance, it’s unclear how a “mythical” cat can help us in life. Yet, here are a few interesting thoughts on this matter.

The skill of living with uncertainty

Schrödinger's Cat symbolizes a situation where the outcome is unclear until the very last moment. In life, we also often find ourselves in a state of “I don’t know if it will work out or not.” Sometimes, it’s worth simply accepting that without a specific action, we’ll never know whether “the cat is alive or dead.”

Avoid fixating on one scenario

Quantum mechanics suggests many possible outcomes. This reminds us that in life, there is often no “only correct” option. Alternatives and backup plans are always possible.

Act instead of endlessly pondering

If we’re constantly afraid to open the “box” out of fear of failure, we’ll remain in a suspended state, not knowing the result. Sometimes, you just need to take a step forward, no matter how scary it seems.

Interesting facts

1. Did Schrödinger dislike cats? A common myth is that Erwin Schrödinger “mocked” cats. In reality, his experiment was never conducted; it was purely a theoretical model designed to demonstrate the paradoxes of quantum theory. Schrödinger used a cat simply as an example of a well-understood creature to illustrate an absolutely absurd situation from the standpoint of common sense.
2. Erwin Schrödinger and his contributions. He is known not only for the cat but also for his equation describing the wave behavior of particles. It is considered one of the “cornerstones” of quantum mechanics.
3. Applications in quantum technologies. The principle of superposition (when a system can exist in multiple states simultaneously) is actively used in developing quantum computers, which promise to be much more powerful than traditional ones.
4. Connection to the many-worlds interpretation. In the “many-worlds” interpretation of quantum mechanics, proposed by Hugh Everett, it is believed that with every measurement, the universe “branches” into several parallel realities. Thus, in one world, the cat is alive, and in another, it is dead. The idea of the many-worlds interpretation was long perceived as science fiction, but now it is seriously discussed, with efforts to find experimental confirmation or refutation.
5. Experiments with macroscopic systems. Scientists have long been experimenting with quantum effects, applying them not only to photons and electrons but also to larger objects (e.g., molecules or “small drums” made of nanomaterials). While no one puts a cat in a box, such experiments help determine how far the “strangeness” of the quantum world extends.
6. Pop culture and memes. “Schrödinger's Cat” has become a truly iconic figure in popular culture, appearing in movies, series, memes, and books. For example, it is featured in the science-popular series “The Big Bang Theory” and numerous science fiction stories that mention parallel universes and quantum phenomena.

A scene from “The Big Bang Theory”

One of the most recent interpretations of Schrödinger's thought experiment is Sheldon Cooper's explanation, a character from the series “The Big Bang Theory,” which he shared with his less-educated neighbor, Penny.

In this short episode, the show’s characters discuss “Schrödinger's Cat” in a casual conversation — of course, with the humor characteristic of the series. Using the paradox, they try to understand relationships and how uncertainty can affect important life decisions. This fragment vividly shows how a scientific concept can become a tool for talking about love, friendship, and personal experiences.

“Schrödinger's Cat” is a vivid example of how science can challenge conventional ideas about the world. It shows that sometimes, facts about reality can be stranger than they seem. For us, it can be a symbol of the fact that sometimes we simply cannot know how things stand until we take specific action.

So, if there is a “box” in your life that you’re afraid to open, perhaps it’s time to stop guessing and look inside. Only then will we truly know which outcome has become reality.