A friend of mine (I’ll call him Ron), who knows that I study physics, likes to talk to me about quantum mechanics. He’s an easy-going guy and likes to joke around. “Hey, is it a particle or is it a wave today?” he’ll say, or, “How many dimensions do we have now?” When the conversation turns more serious, he tells me how he believes in the “quantum universe,” which is greater than what we humans are able to ordinarily perceive. He talks about consciousness, immortality, spirits, and the great cosmic grandeur of the universe, all of which he ties together with the label of “quantum.” These conversations are strange to me. Both of us are using the same two words: quantum mechanics. When Ron thinks about quantum mechanics, he associates it with nonphysical concepts, like spirits. Through my time spent studying physics, I’ve come to understand quantum mechanics as a theory describing the behavior of atoms and subatomic particles. For example, one day our chatting turned to the topic of medicine and how the human body heals itself. Ron told me that the biggest problem with modern medicine is that doctors think of the body as a physical object only. Healing, he said, was a “quantum” effect. I told him that I could make a pretty strong physical argument for why that wasn’t the case. He responded with this story: Once, when playing football, he severely injured his knee. The injury was so bad that he couldn’t bend it or move it. He didn’t have health insurance and didn’t have the cash on hand to pay for medical treatment. One day, he prayed to the universe that he would get better and a “tornado of light came down” and healed his leg. Since then, Ron says, he’s always believed in and respected the quantum universe. I can’t tell Ron that what he described in his story didn’t happen, that his experience was wrong or incorrect in some way. I wasn’t there, so I can’t comment on the accuracy of his narrative. And even the story of how his body healed out of the blue isn’t problematic: as far as I can tell, decades after the story took place, Ron is in good shape and his leg is doing fine. What I found objectionable about the story was how, in the end, Ron attributed his healing to the miraculous intervention of quantum mechanics. Quantum mechanics, in all of its glorious strangeness, is only relevant on inconceivably small scales and at very, very low temperatures. One of the reasons it took humans so long to develop the theory of quantum mechanics is that quantum effects don’t readily appear in everyday life. My [colleagues](http://ultracold.lassp.cornell.edu/) who work to observe quantum mechanics in their experiments use lasers to manipulate [atoms](http://en.wikipedia.org/wiki/Rubidium/) (objects that are 1/10,000,000,000th of a meter in size and weigh around 1/10,000,000,000,000,000,000,000,000th of a kilogram) at temperatures less than 1 Kelvin (about -459 degrees Fahrenheit). At larger sizes and temperatures quantum effects are negligible. The human body is more than a meter long, usually weighs around 50-100 kilograms and, if healthy, maintains a toasty 98 degrees Fahrenheit. Quantum mechanics is important at the atomic level, but on the scales at which people interact with the world it hardly shows up at all. So, even if Ron's leg heals as he said it did, I wouldn't give credit to quantum mechanics. I have been studying physics for years and still quantum mechanics remains utterly baffling to me. The fact that such an abstract theory can tell us so much about the world feels a little bit like a miracle. Quantum mechanics carries with it a number of counterintuitive ideas like the [uncertainty principle](http://opinionator.blogs.nytimes.com/2013/07/21/nothing-to-see-here-demoting-the-uncertainty-principle/) entanglement, or [parallel universes](http://en.wikipedia.org/wiki/Many-worlds_interpretation). These ideas are so abstracted from every day life that the subject begins to take on a supernatural quality. Physics no longer seems like physics- it starts to sound like mysticism. So it makes sense that contemporary culture has seized upon quantum mechanics as a possible explanation for inexplicable things. The theory has so many surprising results that it seems natural to extend it to encompass other things that confuse us, like questions of consciousness. Furthermore, “quantum mechanics” is a term that carries with it the weight of scientific legitimacy. If Ron had said that he had been healed through witchcraft, laying on of hands, or alchemy he would have sounded ridiculous, but attributing his experience to quantum effects allows the story to borrow from the credible reputation of fact-based 20th century science. What my friend doesn’t realize is that terminology is not what makes quantum theory powerful: the scientific methodology supporting quantum mechanics is what matters. It’s important to keep separate quantum mechanics the physical theory and quantum mechanics as a mystical cosmic principle. Despite how confusing it is, quantum mechanics is an empirically motivated and mature theory that gives us a framework to understand physical phenomena like radiation and chemical bonding. This is fundamentally different from applying quantum mechanical concepts to the nature of reality or consciousness. To do so may be a fun philosophical parlor game, but it is baseless speculation without any evidence to motivate the connection between quantum mechanics and the supernatural that it begins with. This confusion is not just restricted to scientific laymen: there are trained researchers working at well-respected research institutions who also [make the same mistake](http://www.quantumconsciousness.org/) my friend Ron does. At the end of the day, speculation that the soul, the afterlife, ESP, or whatever else are quantum effects is unscientific, but at least it isn’t dangerous or harmful in the same way as climate change denial or [refusing to vaccinate your children](http://www.nbcnews.com/health/measles-surges-uk-years-after-vaccine-scare-6C9997438/). It’s closer to something like [intelligent design](http://www.intelligentdesign.org/), which is [fundamentally confused about what science is](http://en.wikipedia.org/wiki/Kitzmiller_v._Dover_Area_School_District/). (We physicists are truly thankful that there is no noisy political movement to teach [Deepak Chopra](https://www.deepakchopra.com/blog/view/900/from_quanta_to_qualia:_the_mystery_of_reality/) alongside physics in high school classrooms.) So I won’t object to my friends’ stories of sudden, unexpected recoveries from illness, but I will react skeptically when I hear that healing has anything to do with quantum mechanics.
^ Credit where credit is due: I took this from XKCD. This may be one of my favorite comics Randall Munroe has ever done. That it came out while I was thinking about this piece was a great coincidence. (A cosmic coincidence explainable through quantum entanglement? Probably not.)
^ Quantum mechanics may be just as mundane as any other materialistic physical theory, but that doesn’t make it any less amazing. My favorite example is how quantum mechanics allows us to understand why the sun works.
^ In case you didn't take the time to click on the link: Seriously, do yourself a favor and click on the link . It's an essay from The Stone that very elegantly describes how the uncertainty principle is far less cosmically mind-blowing than you may have come to believe. It does a beautiful job bringing us back down to earth and carefully explaining the scope of the principle. I must give it credit for having inspired this piece in no small way.