Quantum mechanics

In physics, quantum mechanics is a theoretical framework describing the behavior of energy and matter at small scales (typically no larger than small molecules). Quantum mechanics is a fundamental branch of physics with wide applications in both experimental and theoretical physics. Nearly all fundamental classical theories, including classical mechanics and electromagnetism, have quantum counterparts from which the classical theory can be derived. The notable exception is general relativity. Quantum mechanics provides accurate descriptions for many previously unexplained phenomena such as black body radiation and stable electron orbitals. Quantum mechanical behaviors are rarely observable at macroscopic scales, but dominate atomic and subatomic physics.

A number of religious arguments employ quantum mechanics or moreover a general lack of understanding in quantum mechanics as an argument for religious claims.


 * "Scientists have faith in quantum mechanics, in the same way I have faith in God."
 * Deepak Chopra uses quantum mechanics to justify his New Age claims.
 * What the Bleep Do We Know!? heavily relies on quantum mechanics to make a number of anti-scientific and pseudo-scientific claims.
 * Heisenberg uncertainty principle is often seen invoked as a God of the Gaps argument. We can't know everything (such as a subatomic particles position and momentum at the same time) therefore you can't prove God doesn't exist.

Scientists do not understand quantum effects
While it is true that there are some quantum phenomena that are not yet well understood (as in any branch of science), quantum mechanics is not much more mystifying than other branches of physics. Nuclear power, lasers, transistors, and computational chemistry and materials science are only some of the technologies that have relied on precise predictions from quantum mechanics. In some cases the predictions of quantum mechanical theories have been experimentally verified to absurd precision.

Quantum mechanics does have a reputation for being esoteric, for a few reasons:
 * It is largely based on advanced mathematics (which makes it less accessible).
 * It reveals particles to have a wave-like nature, which makes the theory less intuitive from the perspective of someone familiar only with classical phenomena.
 * The uncertainty principle: for some types of experiments, one cannot calculate precise, certain results, but only the probabilities of various possible results. As an example, a particle moving towards a photographic plate may be in a wave-like state that is spread out and has no particular position. It behaves deterministically and we can predict this state exactly as it changes. However, once it interacts with the plate, it will produce a dark spot in only one location, which cannot be predicted with complete certainty in advance. Physicists are still investigating how interacting with macroscopic objects (like measurement devices) can force a particle to have a specific position (or momentum, or spin state).
 * Entanglement: two particles can become "entangled", in which case interacting with one will change the state of the other, no matter how far away it is. It turns out that quantum uncertainty prevents the transmission of useful information using entanglement alone. However, it is possible to use classical and quantum channels together to send encrypted messages or to facilitate quantum computing.

While these features of quantum mechanics can be both fascinating and frustrating, none undermine scientists' confidence in the validity and usefulness of the theory. Unfortunately, these are the very features exploited by pseudo-scientific ideas, which attempt to borrow credibility from mainstream science by co-opting terminology and exploiting the ignorance of laymen about what quantum mechanics actually says.

Quantum mechanics describes how thought or consciousness affects (or generates) matter
To put it bluntly, quantum mechanics ignores thought and consciousness completely. There's no spot in any equation or algorithm to plug in any information about what people are thinking. The misconception that consciousness has been somehow been proven to affect quantum phenomena is usually based on one of the following.

Poorly controlled experiments/cherry-picked data
Example: Masaru Emoto claims that water crystals can be made more or less beautiful simply by positive or negative thinking directed at the water. He attempts to demonstrate this by exposing water to various messages, freezing the water, and picking photos of water crystals that he thinks will illustrate his point. No independent researcher has been able to replicate these results in a properly controlled experiment, and Emoto does not consider himself a scientist. He has profited considerably from selling books and other products such as special "Indigo Water" based on this questionable research.

Effects of measurement
It is well-established that changing which properties of a particle are measured changes the apparent behavior of the particle. This has led to statements such as "Just the act of observing a particle changes it," or more radically, "Matter has no existence independently from our minds." But in fact this attitude is misguided in (at least) two ways.

Firstly, there are many experiments in which the uncertainty principle is not relevant, where the outcome of an experiment can be predicted precisely in advance. The uncertainty principle has a precise mathematical meaning, and does not simply state that all quantum measurements are unpredictable.

Secondly, in order to see the effects of different measurements, one needs to change the measurement apparatus itself, and it is this change which appears to affect the results, not the mental state of the researcher. In other words, particles only behave differently when measured because researchers have to hit them against something in order to measure them. It's how the experiment impacts the particle that matters. Whether or not some conscious entity is watching the experiment is, as far as we know, irrelevant.

Interpretations of quantum mechanics
The "measurement problem" is one of the longest-standing conundrums in quantum mechanics. When a quantum system is measured (i.e. information about the system is amplified and made macroscopic), this phenomena is described by a unique, probabilistic event that cannot be derived from otherwise deterministic theories of quantum mechanics. That is, one must add a new axiom to quantum mechanics solely to describe measurement. It is not obvious why this should be necessary, and the interpretation of this feature of quantum mechanics has been contentious since the early years of the theory.

There are dozens of proposed interpretations of quantum mechanics that attempt to address this problem, including some that claim that the consciousness of the observer is key to the process, rather than the physical apparatus itself. Unfortunately, most interpretations of quantum mechanics have either been proven wrong (including Albert Einstein's favorite, a local hidden variables theory), or else cannot be scientifically verified because they provide no testable predictions (other than the trivial prediction that quantum mechanics is itself accurate).

One of these interpretations may be correct, but since we know of no way to test them, it is not appropriate to assume any of them. Because of this, it is wholly inappropriate to claim that any of them prove anything about consciousness. Unfortunately, this has not prevented some physicists from claiming that quantum mechanics demonstrates dualism. It's important to realize that the opinions of a few notable scientists on a contentious subject do not carry the same weight as established scientific consensus, particularly when many of these scientists concede that they are approaching the subject philosophically rather than using the scientific method. After all, Einstein's own interpretation of quantum mechanics, based on his personal conviction regarding local realism, turned out to be demonstrably false.

"Quantum" as a buzzword
This one is a favorite of Deeprak Chopra, who discusses "quantum healing", a practice that no actual quantum physics seems to have been involved in creating. However, people who have very little idea of what quantum mechanics really says will tend to assume that "quantum healing" is somehow based on actual physics. This perpetuates misconceptions about what quantum mechanics really says.

Essentially all alternative medicine products that use the word "quantum" do this, as well as many claims regarding the effects of meditation, prayer, or trances. Even if it were true that meditation and prayer could produce miraculous results, there's no reason to suspect that this has anything to do with quantum mechanics until someone can actually demonstrate a connection between quantum effects and conscious thought. The use of the word "quantum" seems to be a marketing ploy for these practices, products, and printed materials, since scientific terms make dubious practices appear more credible.

Quantum mechanics shows that we (humanity, or the whole universe) are all interconnected
In a very trivial sense, we are all interconnected. Humanity is organized into societies that are all in contact with each other on the planet Earth. We all came from matter in the same accretion disk that formed the solar system, and way before that the same matter was packed into a very tight space during the Big Bang. But that's not what is usually meant by this claim. This claim instead is used to suggest that human beings can metaphysically influence events at a distance, or to posit the existence of a universal consciousness (i.e. to support pantheism).

This idea is often supported by simply using "quantum" as a buzzword, but the phenomenon of entanglement is another source for this claim. Entanglement between particles allows them to share information. For example, measuring one particle in a particular way can change the possible results that one could get when measuring the properties of a different particle at a great distance. Albert Einstein famously called this "spooky action at a distance".

However, in order for entanglement to be involved in conscious action (or conscious thought), it would be necessary for entanglement to transmit some kind of useful information. This is actually not the case; quantum uncertainty always prevents this.

A classical analogy would be this: Suppose that person A is in one room and person B is in another. Person C tells them that she will randomly flip a coin and send A the result. Then she will tell B the opposite (i.e. heads if the coin came up tails and vice versa). A and B will both know what the other person has been told (they share information), but they have no way of communicating using this information.

In fact, it is even more difficult to use entanglement to transmit information because if particles interact in the wrong way with macroscopic objects, they are effectively "measured" and lose some of their quantum mechanical properties such as entanglement.

There are still some potential applications for having two particles entangled at a distance. One can use the entangled particles as a way of sharing an encryption key, for instance. But this sort of phenomenon is hardly a convincing mechanism for a metaphysical process like psychic communication or a global consciousness.

"Everything is energy."
More a general physics claim than one specific to quantum mechanics, it is nonetheless occasionally claimed that "Quantum physics has shown that everything is made of energy." Actually, nothing in physics is made of energy, because energy is not a substance, but rather a conserved quantity. Just as nothing is "made of" 70 liters, no one is made out of a certain amount of energy. Nor is anything made out of charge, momentum, or angular momentum. Those are simply properties of objects and systems.

It is true that mass and energy can be converted into one another and thus it can be useful to think of mass as just a form of energy. However, nothing is made of mass either. Things are made out of matter, which is a generic name for all physical substances and not a quantity. Nothing is made out of mass, which is way of quantifying matter but is not a substance any more than volume or total charge are substances.

Things which we think about as being "made of energy", like light or electricity, are generally made up of particles just like everything else. There's no scientific definition of energy that can support this vague idea.

"The God Particle"
This is a name given to an as-yet undiscovered, theoretically predicted particle called the Higgs boson, in a popular science book by the same name. While the book is a generally accurate overview of theoretical physics (as it was in the early 90's), the name it gives to the hypothetical Higgs boson is misleading. The Higgs field would be responsible for giving mass to all particles which have non-zero mass, which is a fairly important role, but which does not necessarily have anything to do with a God. The name is a poetic metaphor which is built up during the book, and has nothing to do with the real properties of the particle or the search for it.

Anyone who claims that the Higgs boson has some bearing on the existence of God almost certainly has no idea what the Higgs boson actually is.