The Parable of the Professor and the Rocks

The Parable of the Professor and the Rocks February 27, 2015

The professor was standing behind his desk in the lecture hall as I came in. That was odd because he usually dashed in just as class was to start.

He looked out at us silently—also odd—and everyone took a seat quickly. He reached under the desk and took out a clear glass jar, the gigantic kind that cafeterias get mayonnaise or pickles in. He set the jar on the desk and then reached under again and took out a box.

From the box, he took out a baseball-sized rock and carefully set it at the bottom of the jar. Then he added more until he placed one last rock in the top.

“Is this full?” he said, the first words he had spoken.

No one said anything. They seemed a little stunned.

“Everyone must vote—is the jar full or not? Raise your hand if you say it’s full.”

Everyone raised their hands.

He pushed the first box aside and reached underneath for another box. This one held sand. He slowly poured sand into the jar, tipping it from side to side until sand spilled onto the desk.

“Now is it full?” he said.

He waited for a bit. When the silence had become painful he reached under the desk again and pulled out a pitcher of water. Very slowly he poured in water and tapped the jar until water spilled out.

“Okay, now it’s full,” he said as he pushed the jar forward. “Now tell me: what is the lesson here?”

I finally raised my hand. “That you can always get more stuff inside?”

“A good guess, but that’s not it.”

No one else wanted to interpret this odd Zen story.

Finally he said, “The lesson is this,” and then he spoke deliberately, “you would never have gotten the rocks in unless you put them in first.

And then he walked out. Class dismissed.

I don’t remember much from that Philosophy course, but I remember that.

In discussing this with friends afterwards, I decided that the jar is your life. It can only hold so much. There are always enough low-priority issues to more than fill it up—television, internet, time wasting, urgent but low-priority tasks at work.

But if you want to get important things done, the rocks must go in first.

(This is a variant of a story that originally appeared in Stephen Covey’s First Things First (1996).)

The real measure of your wealth 
is how much you’d be worth if you lost all your money
— Bernard Meltzer

(This is an update of a post that originally appeared 8/22/12.)

Photo credit: Wikimedia

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  • Castilliano

    Or your life isn’t full without the little things…
    Or the little things can obscure the big things…
    Or the early things will always be bigger to us…
    Or if you focus on the big things you’ll have a hard heart…
    Or expand yourself so that your life can be fuller…
    Or be more fluid so you can reach fullness sooner…
    Or beaches are people too…

    I love Zen phrasings for reflection, but find little guidance from/in them.
    Deepities all.

    There’s a YouTube video with a professor doing this, but he uses chocolate milk at the end, adding, “There’s always room in life for chocolate milk.”

    • Greg G.

      What a sad ending. All that chocolate milk going to waste. Tell me they filtered it.

    • Kodie

      Life is like a jar of rocks and wet sand.

      • MR

        Mama always said that.

  • Aram McLean

    I thought this was going to be the one where he pours the beer in last and then says, ‘The lesson here being that no matter how full your schedule gets, there’s always room for a beer.’

  • OverlappingMagisteria

    Finally he said, “The lesson is this,” and then he spoke deliberately, “you would never have gotten the rocks in unless you put them in first.”

    Not quite… as long as you measure carefully you should be able to fit the same amount of rocks, sand, and water no mater what order you put them in. The only difficulty might be if you put the sand in before the rocks – sand isn’t fluid, so you might have to shake the jar a bit in order to get it to settle up and around the rocks…

    …You might say I’m thinking too much.

    • truth_machine

      You won’t be able to do it without the sand flying out. And you will never be able to get the last rocks into the jar … they just won’t fit because the sand has to *already* be between them for them to make it.

      “You might say I’m thinking too much.”

      No, you’re not thinking enough.

      • OverlappingMagisteria

        Yea, sand before rocks will be difficult. But rocks, water, then sand should work.

        • truth_machine

          Wrong .. you wouldn’t know how much water to add. Again, your “Not quite” and your claim that you’re thinking too much is an example of the Dunning-Kruger effect. You said ” as long as you measure carefully”, but no measuring is necessary when adding rocks, then sand, then water, and no “careful” measurement is possible if you do it in the wrong order. Now run along, dimwit, I’m done with you.

        • OverlappingMagisteria

          Haha… my “thinking too much” was only referencing that the parable in the post is just a parable… of course over analyzing it is silly – the point of story has nothing to do with rocks, sand and water, but about priorities in life. And overall it’s a good parable! We’re just being nit picky. I think the fact that we’ve been arguing about the irrelevant part of the parable demonstrates that very nicely! We’re both spending far too much time thinking about the unimportant part of the parable.

          “Wrong .. you wouldn’t know how much water to add.” I think you could: Put in rocks, pour in water almost to the top, then pour in sand and stop before it overflows. But again.. at this point in time we’ve wasted much more time and thought on the irrelevant part of the parable.

          P.S… sorry for the delay.. I was offline last week. I shall “run along” as you wish now!

        • truth_machine

          I put in little time and got it right; you put in a lot of time and got it wrong, and you continue to … the goal is to first get as many rocks in as possible, then as much sand as possible, then as much water as possible … if you give up that goal, you might as well just fill the jar to the top with water. Now I’m done with you, you silly person. Goodbye.

        • OverlappingMagisteria

          If the stated goal was to “first get as many rocks in as possible, then as much sand as possible, then as much water as possible,” then I’d agree that the order stated would be the easiest (but not the only) method. (…although looks like you baked the order right into it the way you just stated it!) But that goal was never stated – the goal that I was addressing (and quoted in my original post) was to get the rocks in.

          Well, goodbye. It’s been an interesting conversation.

        • truth_machine

          What an intellectually dishonest fool.

    • Kodie

      As long as you measure carefully, how? Have you ever packed up and moved? Does your car have a trunk? Does your house have a garage? Do you have any furniture, a toolbox, a cabinet under your bathroom sink, a junk drawer? You start with the big stuff, that’s just how it’s done.

      • OverlappingMagisteria

        Oh I agree! It’s certainly easier to put the rocks in first. But let’s say you you’ve already determined that the jar can hold X rocks, Y amount of sand and Z water. Then you should be able to fit them in.

        But my comment is a bit tongue in cheek too.

        • Kodie

          How would you measure it?

          But let’s say you you’ve already determined

          See, your idea is to already do this one time and then just to be difficult, prove you can put the items in backwards by taking a long time to do it.

          Or would you calculate the volume of every item, or just accept you can’t put as many rocks in after you already put in too much sand, take it all out and try to fit it in backwards? NO. You’re going to start with the big stuff.

        • OverlappingMagisteria

          “…and then just to be difficult, prove you can put the items in backwards by taking a long time to do it.”

          Oh absolutely I’m being difficult! 🙂 I was in a silly mood with my first post and thought it would be fun to over-analyze the illustration in parable. Of course, the moral of the parable is a great one: prioritize the important things in life. Whether the illustration with the jar can be gamed in some convoluted manner is not really relevant to the point of the parable.

  • Greg G.

    This may be off-topic for any particular article but not so much for the overall topic, but I can’t resist sharing this cartoon I saw on Facebook:

    • He was underneath the couch cushions the whole time!

      (Or behind the curtains. Damn–the dude’s tougher to find than Waldo!)

      • Greg G.

        It’s the white and gold toga that makes him hard to see.

        • Dear Lord, are you blind?? It’s blue and black!

        • Greg G.

          The next person who tells me that will be beaten white and gold.

  • Sophia Sadek

    Some folks insist on focusing on the petty details. After all, they seem so much easier to address than the big problems.

  • truth_machine

    A problem with many analogies is that they are simply wrong because the things being compared don’t have the salient similarities. That’s the case here. Among many other problems with the analogy, I would note that, if you “waste” all your time watching television etc., you won’t have time to rob banks or beat up old people just as much as you won’t have time to get an education or whatever you consider to be the “rocks” of life. The things that occupy life don’t have differing densities and shapes or analogous properties that allow some to fit into the spaces between others. If you want to promote something, do it with valid arguments, not propaganda.

    • There are no turds (robbing banks) in the example. You’re saying that I should’ve added some?

      • truth_machine

        What I wrote was clear enough, and it certainly wasn’t that.

      • Greg G.

        The moral is: Always poop the big turds first, then the little ones, then pee.

    • Guest

      Bob wrote a really good post just two down from this one on the main page. You should check it out.

      • truth_machine

        He has written many good posts. If you’re suggesting that his post about Dunning-Kruger describes me, you’re just being a stupid ass.

  • Brian Westley

    This puts a whole new meaning on Charlie Brown always getting a rock when trick-or-treating.

  • Bob

    When I was a wee laddie engineering student we shared Chem 100 with the lowly Arts and Sciences students who needed a science elective or those who were about to transfer to Chemical Engineering. Our Professor was Doctor Wallace, about 80 years old, strong resemblance of Harry Morgan and spoke EXACTLY like Jimmy Stewart in “It’s A Wonderful Life.” One day we were studying titrations and Jimmy Stewart said “Ok. If you take 50 milliliters of this stuff, for you Arts students that is about a coffee creamer, for the engineers that is about a shot glass ….” Pandemonium ensued. Flasks were pulled. A good time was had by engineers.

    Moral of the story. Fill the glass with rocks, add the vodka, shake don’t stir, drink, repeat.

  • Mick

    My philosophy? Just plod along, doing what comes naturally, and hope for the best. I started out as a fruit picker worked my way up to factory hand and finished my working life as a forklift driver. Now I’m retired and I couldn’t be happier; sitting on my arse all day, surfing the Internet. (Only $2,000 in the bank though.)

  • RichardSRussell

    Truth_Machine makes a valid point about analogies: They’re only valuable insofar as the point to be made is just as congruent with the analogy as the obvious similarities. Put another way, it certainly is possible to compare apples and oranges.* Obvious similarity: both fruits. Obvious difference: color. Subtle difference: acetic vs. citric acid. The point you draw from the comparison is entirely dependent on which of those characteristics you’re trying to evoke with the analogy.

    The parable Bob quotes breaks down when you get to the professor’s conclusion. Yes, it’s not possible to cram the rocks into the jar if it’s already full of sand; that part is true. But if you’d started out filling the jar with the water and omitted the sand, you could still get just as many rocks in. So what lesson is that supposed to teach us?

    I guess the moral of my comment is to pick your analogies and metaphors carefully so they illustrate the point you’re actually trying to make and not simply creating a distraction.

    *General principle: It’s always possible to compare any 2 things, even if the result of the comparison is that they have nothing whatever in common.

  • GubbaBumpkin

    And then the professor said, “the jar is still mostly empty space. So I’m going to insert this neutron star to collapse all the atoms of the rocks and sand and water, and you will be amazed at how much space is left.”
    And then they all died, because neutron stars are dangerous things.

  • Wick Samuel

    I decided that the jar is your life. It can only hold so much. There are always enough low-priority issues to more than fill it up—television, internet, time wasting, urgent but low-priority tasks at work.


  • Dennis Smith

    It’s a interesting story but is probably and “urban legend”. It’s unlikely this ever actually happened even though it’s presented as if it’s a personal story that is an actual personal experience. Unfortunately people take these stories as true.

    You an understand what these things are compelling and why people try to convey ideas in this way, we are a story telling species, just look at the parables of Jesus and the morality tales of Aesop. Nonetheless, true is true and made up is made up.

    The distinction should be clear. It certainly is with Jesus and Aesop.

    • Greg G.

      The title labels it a parable. Isn’t that the ancient term for “urban legend”?

      Covey is apparently a motivational speaker:

      • Dennis Smith

        My point is that a parable is an illustrative story. The teller makes it clear it is only an illustration and does not represent it as true, as having actually occurred. However, these sorts of stories are most often circulated as if they actually occurred, They is the issue for me.

  • wtfwjtd

    This reminds me of the story of the wealthy capitalist, when asked how he acquired his fortune:
    “First, I saved my money, and bought an apple, polished it, and then sold it for a profit. I took the profit, and then bought two apples, and likewise sold them for a profit. Then, my wife’s wealthy father died, and left me a million dollars…”

    • Reminds me of the advice given by an experienced entrepreneur. To make a million dollars, his advice: “First, start with two million dollars …”

      • Kodie

        Borrow money, if you have to, from your parents.

  • Jackson

    And that jar full of rocks turned out to be Albert Einstein.

  • Greg G.

    Noah got all the animals in Ye Olde Arke by filling it with all the largest animals. Then he put in insects and rodents. That reduced the average size of all the animals leaving plenty of room for medium-sized animals.

    • Isn’t mathematics marvelous!

      • Greg G.

        An elephant occupies a certain amount of floor area and volume. Adding two piss-ants reduces the average size by a third. So the three combined would occupy one third the floor area and one ninth of the volume than the elephant would by itself.

        Several years ago, a creationist author did Ark mathematics using the average size of the animals to get the answers he wanted. He ignored the problems.

        • My favorite Ark mathematics problem is the square-cube problem. Double the size of the ark, and the volume of the ark goes up 8-fold. Each beam is 8x as heavy, but its strength is proportional to its cross section, which has only increased 4x. Magnifying a boat makes it more fragile. To keep the strength up, the beams must become thicker, and the useable volume gets less.

        • Greg G.

          Ah, but Noah used gopher wood*, light as balsa, stronger than steel. Unfortunately, the seeds were just too tasty to resist.

          *Too many conversations with creationists.

        • Damn their irrefutable, watertight logic!

  • Rowan

    It started off full of rocks and air. Then it was full of rocks, sand and a bit of air. And then it was full of rocks, sand and water. I’ll leave the implications for the metaphor to the reader.