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Schrodinger – The Uncertainty Principle
Today, people use Heisenberg’s Uncertainty Principle to resurrect George Berkeley’s 18th century philosophy, encapsulated by the Latin phrase Esse est percipi(“To be is to be perceived”). Berkeley’s views represented an extreme form of empiricism. He insisted that we could not know that an object exists, only that our minds perceive something resembling that object. However, this didn’t mean that objects popped in and out of existence, only appearing when someone observed them, since, for Berkeley, all things existed under the watchful eye of God.

Albert Einstein felt uncomfortable with the ramifications of Heisenberg’s Uncertainty Principle and the Copenhagen interpretation of quantum mechanics that followed. Heisenberg and Bohr argued that we could never know with certainty the position of a subatomic particle. We could only offer a probability distribution to describe the position of the particle. Bohr concluded that subatomic particles exist in a superposition of states and, by extension, that they have no determined location prior to measurement. Underlying reality was thus considered indeterminate. This notion struck Einstein as completely absurd, and in the mid-1920s Einstein began collaborating with Erwin Schrödinger to extract the reality from this absurdity.

Schrodinger and the cat
Schrödinger devised a thought experiment about a cat that clarified the absurdity of the Copenhagen interpretation. Schrödinger’s cat remains a familiar concept today. Schrödinger described his idea like this:

    A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out.1
So, is the cat dead or alive? According to the Copenhagen interpretation, the cat exists inside the chamber as a hybrid, both half-dead and half-alive. Once someone opens the chamber door they observe one or the other, either a dead cat or a live cat. Seems pretty ridiculous, doesn’t it? That’s because it is. In fact, Schrödinger offered this thought experiment as a refutation of the Copenhagen interpretation of quantum mechanics.

Schrodinger – His philosophy still persists today
Today, the controversy still occasionally comes to the forefront of discussion. On November 3, 2007 New Scientistpublished an article by Mark Buchanan discussing the work of Joy Christian at the University of Oxford. Christian “claims that physicists’ supposed proofs of the impossibility of more ‘realistic’ theories rest on false assumptions and so don’t prove much at all.”

    ‘Contrary to the received wisdom,’ he says, ‘quantum theory doesn’t rule out the possibility of a deeper theory, even one that might be fully deterministic.’ Christian’s conclusion follows from a relatively simple calculation using alternative mathematics, described in a paper now under review at the journal Physical Review Letters… Einstein might have been relieved, and it’s a shot in the arm for those seeking a deeper reality beyond quantum theory that might be more ‘reasonable’ and akin to classical physics.2
For Victor J. Stenger “everything which happens in the universe is not predestined at all.” Yet, a deeper theory is still being sought, which many think will restore a certain degree of determinism to the natural world.

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1 Erwin Schrodinger, “The Present Situation in Quantum Mechanics,” Proceedings of the American Philosophical Society (Nov. 29, 1935). (
2 Mark Buchanan, “Quantum Untanglement,” New Scientist (3 November 2007), 37, 38.

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