In physics, the uncertainty principle (or, more fully, Heisenberg's uncertainty principle) is the idea that when you're trying to observe two different things, the more closely you observe one of the things, the more uncertain the other thing becomes.
I'll let Arthur M. Lesk, professor and biochemist, define the principle more authoritatively for us: "What Heisenberg's uncertainty principle asserts is that for no state of any system can all dynamical variables be arbitrarily well-determined." 

Let's also let the OED weigh in here. It defines the uncertainty principle as the idea "that certain pairs of observables (e.g. the momentum and position of a particle, the energy and lifetime of a quantum level) cannot both be precisely and simultaneously known, and that as one of any pair is more exactly defined, the other becomes more uncertain."

Outside of science, some people use the phrase "uncertainty principle" to mean the idea that fine-tuning one thing tends to make some other thing less fine-tuned. 

If you're a physicist, that general, watered-down usage of the term might make you tear your hair out. That's okay. The frazzled hair looks good on you. Very mad scientist.

Part of speech:

Noun: "Their findings are consistent with the uncertainty principle."

Other forms: 

You can capitalize it, if you like: "the Uncertainty Principle." Or include the name of its formulator: "Heisenberg's Uncertainty Principle."

how to use it:

I'm generally pretty chill about letting precise terms from academic fields trickle into general conversation, even though that means regular folks like me are applying the terms more broadly than their coiners intended. You might not be so chill about it, and that's okay.

If you do decide to use the term "uncertainty principle," even though it's rare, it practically defines itself and therefore shouldn't confuse your listeners. You might talk about events that prove, obey, test, strain, defy, or violate the uncertainty principle.

examples:

"Robert Penn Warren is one of the few distinguished literary men who can aim a novel at the gut and not offend the head. The reason seems to be that even in the age of the Uncertainty Principle and culture fracture, Warren has not lost his sense of life as a sustained drama."
  — R. Z. Sheppard, Time, 14 March 1977

"The AAM trumpets in the two D Major suites... had the airy, tonally unpredictable, raw natural brassiness that many composers over the past 100 years have tried to mimic for special effects. They are so difficult to control that they appear to have their own uncertainty principle when it comes to pitch and tone."
   — Mark Swed, Los Angeles Times, 13 November 2014

has this page helped you understand "the uncertainty principle"?

Awesome, I'm glad it helped!

Thanks for letting me know!
If you have any questions about this term, please message me at Liesl@HiloTutor.com.

study it:

Explain the meaning of "uncertainty principle" without saying "indeterminacy principle" or "you can't do everything perfectly all at once."

try it out:

According to Philip Brandes of the Los Angeles Times, Michael Frayn's play Copenhagen questions "how we can make a moral judgment about anyone without some knowledge of their intentions," and therefore "maps the quantum uncertainty principle to the heart of human nature."

So it's partly just a play on words: Copenhagen is about Heisenberg! But it's also an interesting comment, right? That the heart of human nature can never be truly known, maybe because it's too hard to pin down people's intentions.

With this idea in mind, try talking about a character (in any fictional work) that you find complex. Maybe it's Iago, or Professor Snape, or Walter White. What is this character's motivations or intentions, and is it possible for the audience to really know this character's heart? Is the uncertainty principle at work here, or no?

If you like, use this space to write. (To save your work, copy and paste it into an email or a document.)

before you review, play:

Try to spend 20 seconds or more on the game below. Don’t skip straight to the review—first, let your working memory empty out.

Our game for April: Word Choice Chuckles!

I'll give you a snippet of text that I spotted in the wild, with a word or phrase removed. See if you can fill one in that'll give the reader a chuckle. (Here are some examples.) Be cheesy. Be punny. Get in there and make me proud.

Try this last one today:

"'She can write whatever she wants': Martha Stewart _____s on the end of a friendship with Ina Garten"

Meaning of the missing word: "divulges."

To see one possible answer, scroll all the way down.

review this term:

1. The opposite of the UNCERTAINTY PRINCIPLE could be the CERTAINTY PRINCIPLE, which, in general conversation, could mean

A. the idea that as you get clarity or precision on one area, other areas also come into clarity or precision.
B. the idea that your gut instincts or sense of intuition will always tell you the right course of action to take.
C. the idea that as groups come to a decision together, even if that decision is a terrible one, they will convince each other that it is an excellent one.

2. Reviewing the novel How to Tell Toledo From the Night Sky, Ron Charles wrote: "Will these two star-aligned nerds end up together? Unfortunately, there is no uncertainty principle at work in this romantic calculation." Charles probably means that, in the novel's plot, there's no _____.

A. spark of chemistry, only awkwardness
B. sense of wobbling dominance between competing forces, only the inexorable hand of fate
C. trajectory of moral development, only static characters who staunchly resist the world's temptations

Answers to the review questions: 1. A (Choice C is pretty close to the meaning of "groupthink.") 2. B From the game: "'She can write whatever she wants': Martha Stewart dishes on the end of a friendship with Ina Garten"  — Joy Saha, Salon, 23 October 2024

a final word:

I hope you're enjoying Make Your Point. It's made with love. I'm Liesl Johnson, a reading and writing tutor on a mission to explore, illuminate, and celebrate words. From my blog: On vocabulary...       36 ways to study words.       Why we forget words, & how to remember them.       How to use sophisticated words without being awkward. On writing...       How to improve any sentence.       How to motivate our kids to write.       How to stop procrastinating and start writing.       How to bulk up your writing when you have to meet a word count. From my heart: a profound thanks to the generous patrons, donors, and sponsors that make it possible for me to write these emails. If you'd like to be a patron or a donor, please click here. If you'd like to be a sponsor and include your ad in an issue, please contact me at Liesl@HiloTutor.com. A disclaimer: When I write definitions, I use plain language and stick to the words' common, useful applications. If you're interested in authoritative and multiple definitions of words, I encourage you to check a dictionary. Also, because I'm American, I stick to American English when I share words' meanings, usage, and pronunciations; these elements sometimes vary across world Englishes.