One of the common ideas about Quantum Theory is that some things don’t happen until someone observes the experiment. Until the observation, events are said to be in superposition – a particle is in all possible states, until someone observes it; when the observation is made, the particle is found to be in only one state.
Erwin Schrödinger found this idea objectionable. He produced a thought experiment that has come to be known as Schrödinger’s Cat. In this experiment, a cat is placed into a box with a radioactive substance, a detector, a bottle of poison, and a hammer. The radioactive substance has a 50% likelihood of producing a particle. If the particle is produced, the detector senses it, causing the hammer to break the bottle of poison, killing the cat. If no particle is produced, the cat is left alive.
Schrödinger’s notion was that, until the box was open to observe the cat, it was in a superposition state, both alive and dead. Schrödinger wanted this to be an argument reductio ad absurdum. That is, an argument which leads to an absurd conclusion, thus showing it is not true. Sadly, Schrödinger did not accomplish his goal.
Schrödinger’s Cat was taken as evidence of the odd things that could happen with Quantum Theory. The cat’s fate is undetermined, until someone looks inside the box. The superposition state collapses when someone observes it. A great deal of nonsense has arisen from this claim, often presented in mystical terms. Physics depends on a conscious mind to cause quantum events to happen.
Actually, an observation is not necessary, for a superposition state to collapse. It can be collapsed by a measurement, which can be done by an inanimate machine such as a Geiger counter. Or a detector as in the experiment. No observer is needed; no conscious mind. Just some interaction with the macro world.
I think some of this confusion arises from scientists not considering the philosophical aspects of reality. They’re struggling with issues without clearly answering important questions about existence, truth, and similar topics.
For example, the idea of superposition seems to say that reality can exist in different states at the same time, and will remain that way until an observation has been made. We might simplify our dilemma if we only recognize that, until we observe something, we cannot know anything about it.
Einstein famously asked whether, when he doesn’t look at the Moon, the Moon ceases to exist. He didn’t like the quantum indeterminism. His point is valid. It’s not that the Moon (or anything else) ceases to exist if no one observes it. It’s that we cannot know anything about it, unless we do observe it.
If I don’t look at the Moon, I cannot know anything about it – including, whether it exists. Of course I assume it exists, but I can’t prove it.
There is a philosophical puzzle that goes, “If a tree falls in the forest with no one to hear, does it make a sound?” Of course we assume it does. Every time something heavy falls, we hear some sort of noise. If a whole tree fell over, it surely would make a noise. The problem is, we can’t prove it. We can’t know anything about what we do not observe.
When it comes to particles, a similar logic applies. A particle that is said to be in “superposition” is simply one that we don’t yet know about. Until we observe it, it remains unknown. Observing the particle doesn’t cause the superposition to collapse. It simply lets us know what the particle did…
The Observer Effect
One of the common ideas about Quantum Theory is that some things don’t happen until someone observes the experiment. Until the observation, events are said to be in superposition – a particle is in all possible states, until someone observes it; when the observation is made, the particle is found to be in only one state.
Erwin Schrödinger found this idea objectionable. He produced a thought experiment that has come to be known as Schrödinger’s Cat. In this experiment, a cat is placed into a box with a radioactive substance, a detector, a bottle of poison, and a hammer. The radioactive substance has a 50% likelihood of producing a particle. If the particle is produced, the detector senses it, causing the hammer to break the bottle of poison, killing the cat. If no particle is produced, the cat is left alive.
Schrödinger’s notion was that, until the box was open to observe the cat, it was in a superposition state, both alive and dead. Schrödinger wanted this to be an argument reductio ad absurdum. That is, an argument which leads to an absurd conclusion, thus showing it is not true. Sadly, Schrödinger did not accomplish his goal.
Schrödinger’s Cat was taken as evidence of the odd things that could happen with Quantum Theory. The cat’s fate is undetermined, until someone looks inside the box. The superposition state collapses when someone observes it. A great deal of nonsense has arisen from this claim, often presented in mystical terms. Physics depends on a conscious mind to cause quantum events to happen.
Actually, an observation is not necessary, for a superposition state to collapse. It can be collapsed by a measurement, which can be done by an inanimate machine such as a Geiger counter. Or a detector as in the experiment. No observer is needed; no conscious mind. Just some interaction with the macro world.
I think some of this confusion arises from scientists not considering the philosophical aspects of reality. They’re struggling with issues without clearly answering important questions about existence, truth, and similar topics.
For example, the idea of superposition seems to say that reality can exist in different states at the same time, and will remain that way until an observation has been made. We might simplify our dilemma if we only recognize that, until we observe something, we cannot know anything about it.
Einstein famously asked whether, when he doesn’t look at the Moon, the Moon ceases to exist. He didn’t like the quantum indeterminism. His point is valid. It’s not that the Moon (or anything else) ceases to exist if no one observes it. It’s that we cannot know anything about it, unless we do observe it.
If I don’t look at the Moon, I cannot know anything about it – including, whether it exists. Of course I assume it exists, but I can’t prove it.
There is a philosophical puzzle that goes, “If a tree falls in the forest with no one to hear, does it make a sound?” Of course we assume it does. Every time something heavy falls, we hear some sort of noise. If a whole tree fell over, it surely would make a noise. The problem is, we can’t prove it. We can’t know anything about what we do not observe.
When it comes to particles, a similar logic applies. A particle that is said to be in “superposition” is simply one that we don’t yet know about. Until we observe it, it remains unknown. Observing the particle doesn’t cause the superposition to collapse. It simply lets us know what the particle did…