Schrödinger's Cat
Schrödinger's Cat is a 1935 thought experiment by physicist Erwin Schrödinger demonstrating the apparent absurdity of applying quantum superposition to macroscopic objects. A cat is placed in a sealed box with a quantum device that has a 50% chance of releasing poison. Before the box is opened, quantum mechanics suggests the cat is in superposition, simultaneously alive and dead. The thought experiment was intended as a reductio ad absurdum of the Copenhagen interpretation, illustrating that quantum mechanics cannot be the complete story of physical reality.
Schrödinger designed the thought experiment specifically to criticize the Copenhagen interpretation. His point: if quantum superposition is a real physical phenomenon and not just a description of our knowledge, then macroscopic objects should also be in superposition, which leads to the absurd conclusion of a simultaneously living and dead cat. Either quantum mechanics doesn't apply to large objects (in which case where does the classical/quantum boundary fall?), or the Copenhagen interpretation's 'measurement collapses wave function' is physically meaningless, or reality is stranger than common sense allows.
Different interpretations of quantum mechanics respond differently. The Copenhagen interpretation: the cat is in superposition until observed, don't ask what 'really' happens inside, just use the formalism. The Many-Worlds interpretation (Everett, 1957): the wave function never collapses, instead, the universe branches, and in one branch the cat is alive, in another it is dead. Both branches are equally real. Objective collapse theories: there's a physical mechanism that collapses the wave function at some scale, and the cat triggers it. Each interpretation has different ontological commitments and different problems.
Predictive History invokes Schrödinger's Cat for its philosophical rather than physical implications: the thought experiment demonstrates that our intuitions about 'objective reality' are not reliable guides to what physics actually describes. Reality at the quantum level doesn't behave like reality at the scale of human experience. This is consistent with Kant's claim that the phenomenal world (experienced reality) is not the same as the noumenal world (reality as it is), and with the esoteric tradition's claim that ordinary human experience is a filtered, constructed version of a deeper reality.
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Frequently asked questions
What is Schrödinger's Cat and what does it prove? ＋
Schrödinger's Cat is a 1935 thought experiment: a cat in a sealed box with a 50% chance of death from a quantum device is, according to quantum mechanics, simultaneously alive and dead until the box is opened. Schrödinger designed it as a critique, not a marvel, his point was that applying quantum superposition to macroscopic objects leads to absurdity. The thought experiment shows that quantum mechanics, taken literally, conflicts with classical physical intuitions about objective reality.
Is Schrödinger's Cat actually simultaneously alive and dead? ＋
This depends on interpretation. The Copenhagen interpretation: yes, the cat is in superposition until observed, but we shouldn't ask what 'really' happens. Many-Worlds: the universe branches, and in both branches a different outcome is real. Objective collapse: a physical collapse mechanism triggers before macroscopic superposition can occur. No consensus exists. The honest answer: we don't know, and the disagreement reveals that quantum mechanics is incomplete or that our concept of objective reality requires replacement.