QM and Observers
There is a widely repeated misrepresentation of quantum mechanics where people think that consciousness is needed to observe a system in order for the superpositions to be resolved. This page is dedicated to exploring this misconception.
An "observer" in the sense of quantum mechanics is in fact ANY interaction with another part of the universe. A system can remain in a superposition of two or more status until it interacts with anything else, and then is decoheres, resolving to a finite state.
"Observation" means physical interaction, not perception. The universe is perfectly capable of collapsing superpositions all by itself.
Setting
Someone Facebook made this claim in the middle of a discussion on the mind:
The brain does not even physically exist unless a skull is cut open to observe it. That’s quantum mechanics.
This write apparently actually believes that, and it echoes much of what you hear elsewhere:
Quantum Mysticism
This interpretation that consciousness is needed as part of quantum mechanics has been given the name quantum mysticism.
The idea that "consciousness causes collapse" is attributed to Eugene Wigner who first wrote about it in his 1961 article "Remarks on the mind-body question" and developed it further during the 1960s.
However, Wigner later renounced this position in the 1970s. In 1984, he writes that he was convinced out of it by the 1970 work of H. Dieter Zeh on quantum decoherence and macroscopic quantum phenomena.
Ultimately, Wigner's renunciation of the consciousness-causes-collapse interpretation reflects a broader consensus in the physics community that consciousness is not necessary for the collapse of the wave function, as decoherence provides a more satisfactory explanation of quantum measurement.
The idea of consciousness causing collapse has been promoted and developed by Henry Stapp, a member of the Fundamental Fysiks Group, since 1993.
Juan Miguel Marin gave us an update in 2009 with" "‘Mysticism’ in quantum mechanics: the forgotten controversy".
What QM Pioneers Thought
Erwin Schrödinger's lectures published as ‘Mind and Matter’
Schrödinger actually invented his famous cat scenario to show how ABSURD it would be if consciousness were required. He was being satirical — pointing out that you'd have to say a cat is simultaneously alive and dead until a person looks, which is obviously ridiculous. The cat itself, the detector, the poison vial — these are all physical systems that interact with and "measure" the atom long before any human opens the box.
According to Werner Heisenberg recollections in "Physics and Beyond", Niels Bohr is said to have rejected the necessity of a conscious observer in quantum mechanics as early as 1927.
Poor Choice of Wording
Physicists chose the word "observation" poorly. It was an early term that stuck, but it has nothing to do with awareness, eyes, or minds. A better word would be "interaction" or "entanglement with the environment." The moment you swap the word out, the mysticism largely dissolves.
What is "Observation"?
An "observer" in the sense of quantum mechanics is in fact ANY interaction. The particle can be in a superposition of states UNTIL it interacts with something that distinguished it. That is an "observer" in the sense that QM means it.
Decoherence happens when a quantum system becomes entangled with its surrounding environment — meaning any physical interaction that causes information about the particle's state to "leak out" into the world. This can be:
- A photon bouncing off the particle — no person needed
- Air molecules colliding with it — no person needed
- A detector registering a signal — no person needed
- Even the particle interacting with a nearby electric field — no person needed
The critical point: once the environment "knows" which state the particle is in — even if no person ever reads the result — superposition is destroyed. The universe doesn't wait for a human to check.
Answer this Question
Decoherence happens in stars, in nuclear reactions, in chemistry on the ocean floor billions of years before any conscious being existed. Are you saying superposition was never broken until the first mind came along to observe it?