If we could preserve only one sentence…

Ian Leslie writes to me:

John Lanchester in the LRB:

“Richard Feynman was once asked what he would pass on if the whole edifice of modern scientific knowledge had been lost, and all he could give to posterity was a single sentence. What axiom would convey the maximum amount of scientific information in the fewest possible words? His candidate was ‘all things are made of atoms.’ In a similar spirit, if the whole ramshackle structure of contemporary macroeconomics vanished into thin air and the field had to be reconstructed from scratch, the sentence which packs as much of the discipline into the fewest possible words might be ‘governments are not households.’ “

At the very least I would ask for “In the short run, governments are not households.”  I might even consider “Today is a long run from some time back.”  And I have a suspicion what Scott Sumner would say.

Throughout keep in mind that 99% of all historic cycles have been “real business cycles,” and that sovereign bankruptcy is a historical norm, even though today many major sovereigns are quite creditworthy.


" In a similar spirit, if the whole ramshackle structure of contemporary macroeconomics vanished into thin air..." Why mess up a good thing by trying to revive it?

the teen reaction to a system that's not working for you as you wish.....burn it to ashes.

Macroeconomics is not working for me? For whom is it working? What are the greatest achievements of macroeconomics? I just hear Jared Bernstein argue that "governments are not households", so I guess the word is out on the left. If people get the mistaken notion that governments are like households, they might begin to question some of the Obama admin's profligacy.

Precisely. Exactly whom is the macroeconomy working for?

From the article, referring to the UK:
"That’s what they set out to do. In June 2010, in his first budget, Osborne said the structural deficit was 4.8 per cent, and that with three years of reduced spending, the figure would be down to 1.9 per cent. So how’s that going? Well, by the end of those three years, after £59 billion of tax rises and spending cuts, the figure is set to be 4.3 per cent. "

Historically the US's structural deficit has been around 3%, I think. I suspect it's now higher. Maybe much higher.

Would anyone care to hazard a guess as to what the US government deficit will average over the 2013-2016 period? 5%? 6%? 8%? ...

Funny that Feynman chose that sentence when we already know that it does't work: Democritus & Leucippus had lines that read almost exactly like that, yet it still took millennia to get real science...

Hard to better it though. I cannot think of anything else even remotely close to "all things are made of atoms" in science.


F=ma, or maybe just a single explanation of math notation such as: a^2=a*a or 0 is a symbol for a value of nothing.

Both of those in the long run would be a lot more usefyl than atoms. Science made a huge amount of progress before it needed to deal with atoms. But to defend Democritus, atomic theory was probably influential in a huge number of underestimated ways mostly because Lucretius preserved the theory and was such a fantastic Latinist.

In the wold of phisics, I would have to go with Newton's First law.

"Objects in motion tend to stay in motion."

I think it is more informative than "For every action there is an equal and oposite reaction" but that one is good, too.

Apparently my previous sentence got eaten by the ether.

I'm going with the Teach a man to Fish approach:
"Identify a problem, collect relevant data, formulate a hypothesis based on the data and finally empirically test your hypothesis."

I agree with JWatts. The Feynman statement is disappointing. I would go with "Experiments can find, and mathematics can express, the laws of nature."

That should get the folks trying to rebuild up to about 1950 in their rediscovery of science.

Feynman didn't consider methodological or mathematical issues to be "Science." He quite explicitly stated that Math is not Science on many occasions. Whether you agree or not, that was Feynman's view.

Hard to better it? Really? It isn't even true!

I am surprised he came up with such a poor sentence. Surely a much better one would be "Experimental falsification is much better than judicial combustion".

Once people get the idea that scientific issues are decided by peer review and not burning each other, all else follows.

Yeah, it's worthless without knowing a lot of other things. I'll say "you can do a lot of cool things by spinning a magnet around copper wire." Needs a bit of elaboration to be useful, but it would fit in a sentence.

Even "you can turn lead into gold, but it's really never going to be worth your time"

For human well-being, how about "most disease is caused by invisible creatures getting inside you and growing, and those creatures can be washed off surfaces and tools and skin with soap and water, or killed with heat or alcohol or acids."

For making sense of the world, "Living things pass many of their traits to their descendants, the descendants with the most useful traits tend to be the most successful at having descendants of their own, and that largely explains how all the living things here now came to look like they do."

For a formula for building science back up, maybe "The best way to find out whether you understand the world is to design an experiment whose outcomes you predict based on your current understanding, and then run the experiment; if the outcome isn't what you expected, then you learn something."

I'd go with something like your third suggestion. Or maybe just, "Test your ideas with careful empirical work."

Good call on the sanitation issue. I might get even simpler... "Always wash your hands after you poop."

"...and don't poop where you drink."

The problem with that one sentence is that it presupposes all sorts of understanding about what an "atom" is. Hell, about what a "thing" is. "Ah," the sixth century bc philosopher might say, "so my soul is made of atoms."

Urso hits it square. God bless Richard Feynman, but he is wrong in every way possible--even on his own terms of glib materialism. An atom, after all, is a "thing," but it is neither fundamental nor itself made of atoms. So this idea doesnt' carry us very far at all. And that's even stipulating that "things" are identical with "material objects."

A serious thinker who had been given Feynman's pearl of great price could only conclude that 20th century scientists hadn't thought very hard about what "things" are or how they are constituted. Aristotle did a lot of work on physical things ("ta onta"), and liked to talk about them as compounds of matter and form--and of the two, he regarded form as infinitely more important than matter. The particular atoms that make up me or you at this moment are pretty trivial. If you ask me to tell me a little about myself and I say, "Well, I am so many kilograms of hydrogren, so many of oxygen, so many of carbon, and a sprinkle of manganese," you'd think I was mad. But hey, you ask a particle physicist about reality, and he tells you about particle physics.

You should look up that lecture sometime and read Feynman's entire comment. Then you might realize how foolish your comment looks to those of us who have.

Have done, thanks. Ages ago. And stand firmly behind my comments. Feynman was a brilliant thinker in a thousand ways, but even he had his off moments, and this was one of them.

By the way, the terms of the exercise allow only a single sentence to be passed on to posterity. So the expanded context is of questionable value. And I am aware that the complete sentence points at both gravitational and electromagnetic/nuclear forces which operate at different scales, et cetera. Still. I'm not being cute here: equating "things" with "material objects" is questionable(*), and analyzing material objects as being necessarily made of atoms is in fact wrong(**). As for looking foolish, I am foolish, and deserve to be reminded of it often. How do you feel about looking blinkered and narrow-minded?

(*) The position that the number three, the Pythagorean Theorem, and "War and Peace" are not "things" is interesting, profound, and eminently defensible. But it is not obvious, not proven, and not much in favor at present.

(**)See above comment. This oxygen atom right here--the one I'm pointing to--is made of things that are not atoms.

The context of the sentence adds information. "All things are made of atoms" might not go very far, but "All things are made of atoms" + "This sentence was singled out as the one to transmit to posterity" could lead somewhere very different. Like with Shannon's anecdote of his brother saying "I could tell you something," the statement might not say much in itself, but that his brother chose to say it turned out to be sufficient to solve the puzzle.

Ha, I came here to post my own reply and found out I'd been ninja'd. http://lesswrong.com/r/discussion/lw/g7p/just_one_sentence/

> When was the atomic hypothesis confirmed? If I recall correctly, it was only when chemists started noticing that the outputs of chemical reactions tended to factorize a certain way, which is to say that it took millennia after Democritus to get the point where the atomic hypothesis started making clearly relevant experimental predictions.

> How about, "Stop trying to sound wise and come up with theories that make precise predictions about things you can measure in numbers."

> I noticed this on Marginal Revolution, so I shall also state my candidate for the one most important sentence about macroeconomics: "You can't eat gold, so figure out how the heck money is relevant to making countries actually produce more or less food." This is a pretty large advance on how kings used to think before economics. I mean, Scott Sumner is usually pretty savvy (so is Richard Feynman btw) but his instruction to try to understand money is likely to fall on deaf ears, if it's just that one sentence. Think about money? Everyone wants more money! Yay, money! Let's build more gold mines! And "In the short run, governments are not households"? Really, Prof. Cowen? That's what you'd pass on to the next generation as they climb up from the radioactive soil?"

And I have a suspicion what Scott Sumner would say.

I'd bet on "Low interest rates are not the same as loose monetary policy."

"A government is not a household"

Obvious and probable exaggeration at the same time.

Do they know they aren't like households? If I decide to cut my gas budget, all of a sudden my revenue also drops.

They are basically begging the question on aggregates, in other words.

"What's an atom?"

Is the law of comparative advantage "modern" and statable in one sentence? That could easily be the winner. Societies seem to have a tendency towards mercantilism and this has held back quite a bit of development. Maybe "the economy cannot be stimulated" or "the gold standard is bad for the economy" as there was [and, obviously, is] a tendency towards those bad ideas as well.

"Most sicknesses are caused by germs and can be prevented with cleanliness" seems like a much more...practical...sentence for general science than what Feynman came up with.

+1 for comparative advantage - probably the single most important economic concept, IMHO.

EconLib has a good one-sentence definition: A person has a comparative advantage at producing something if he can produce it at lower cost than anyone else.


That should be: "...at a lower opportunity cost than anyone else.

Comparitive advantage in one sentence?

"Do what you do best."

"Do what you do best, even if someone else can do it better than you."

If you only have one sentence... Make it as long as possible.

"Make it as long as possible."

Is that the sentence?

This made me laugh.

You must be familiar with patent claims then (they are all one run-on sentence).

"At the very least I would ask for 'In the short run, governments are not households.' "

A prime example of how to take a perfectly good statement and clog it up with blather through needless qualification.

To summarize macro in one sentence, I would quote Public Enemy: "it's harder than you think."

One problem with "governments are not households": local governments are governments, and for purposes of macro they are a lot like households.

A more general statement might be "beware the fallacy of composition."

Another idea would be "Remember the differences between financial claims and real wealth."

Is Iceland like a household?

My sentence would be, "Governments are like households," and hopefully that would nip a lot of things in the bud right there.

You'll always get hit by a recession you could never predict.

How about "inflation is always a monetary phenonomen, but allowing that fiscal authorities can create money."

"Trade Benefits Everyone"?

It does no such thing. It benefits a group of winners so much that they could, if they wished, compensate the losers for their losses and still be better off than they were before.

In the context of Macro?

Or, I should say, try convincing most economists of that......

Trades are usually (not always) beneficial to both sides, i.e. they often have no losers, only winners.

Interestingly, humans are the only animals that really understand trade, it's arguably the most important distinguishing characteristic of humans. No other animal (even our close primate relatives) will trade less of something they like more for more of something they like less, they only understand "I like this more than that."

"Trades are usually (not always) beneficial to both sides, i.e. they often have no losers, only winners."

The losers, if there are any, are not a party to the trade.

Good on Urso again. A voluntary trade is presumed to benefit the parties to that trade ONLY. There is just a _little_ bit of distance between "the two parties to a trade" and "everyone."

So maybe we're learning some things about the usefulness of collapsing entire sciences into one-sentence bromides...

Also, many losers lose because *the trades they wanted* did not happen, (e.g. they were not hired). The problem is still (roughly) not enough trading. More voluntary trades = more wins.

> Trades are usually (not always) beneficial to both sides

What do people say about securities markets? If one guy buys IBM and the other guy sells it, leaving aside taxes, liquidity needs, and other complications, one of them is right and one is wrong, right? One wins and one losses, right?

Well, yes. If you leave out lots of reasons someone might make a trade it will out that there must be a winner and a loser.

In fact, I think that is usually the case, but not, as you seem to imply, always.

One guy wants IBM stock more than he wants cash and the other guy wants cash more than he wants IBM stock.

Sbard, that is only true at the moment the sale is made -- either or both might rue the trade as soon as the very next day. So while it's true that trades make both parties immediately happier, there's no guarantee that'll hold. A junky is happy to get his hit, but I doubt years later he'll look back on his life and think "man I sure am glad I did all that heroin."

Obviously I don't want to come across as anti-trade here. It's more that, as someone else said upthread, these little pat explanations just don't do merit to the complexities of these disciplines. And that's assuming anyone even listens. Hell, I'd be hard-pressed to come up with a single sentence more helpful than "thou shalt not kill," but we haven't exactly done great with that one.

Urso -- well, it's impossible to know. The guy who sold the IBM stock is probably usually still happier to have the cash unless the stock goes way, way up -- and in any case, he lacks perfect knowledge of the future, so he can only make the trades he believes are beneficial based on his limited information.

OTOH it's true some traders will be buying and selling IBM strictly on the belief it will go up/down in value, and in those cases markets must have winners and losers. It's just important to realize that the vast majority of transactions in the economy are win-win rather than speculative.

"Markets are a phenomenon of human activity, but not of human design."


This is perfect

I think factually that's incorrect. Historically someone or a group had to work to create particular markets. For instance, both the NYSE and NASDAQ are designed markets. So is your local grocery store.

I agree people will see to trade for benefit.

Maybe work in a good restatement of Say's Law with the implication that markets will necessarily arise?

The buying and selling of food predates grocery stores. The market already existed, the grocer applied skills to better the process. Similar to the buying and selling of commercial enterprises. Both compete with other methods that accomplish the same thing in different ways. The market existed already, these forms arose to meet demand. Nobody came up with a fully formed supermarket. They developed from the iterative process of failure. And both continue to change in response to market changes.

"Historically someone or a group had to work to create particular markets."

This is especially true for deregulated wholesale electricity markets. The massive coordination problems inherent in balancing the grid and the demand by consumers of a stable and reliable supply above economic concerns necessitates an intentional, complex design.

Feynman actually said:

"all things are made of atoms — little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another."

Source: http://www.brainpickings.org/index.php/2012/09/11/richard-feynman-lectures-on-physics/

A little better, but most of the added part is totally superfluous. So the atoms are in pereptual motion. So what? So they attract/repel each other. So what? What is a caveman going to do with any of that information. It's basically gibberish, and it's going to take him eons to develop the technology necessary to even detect an atom, much less figure out what to do with it. In the meantime you'd have generations of would-be philosophers coming up with what we'd see as hilariously off-the-wall explanations for what these "atoms" are that the Great Prophet Feynman spoke of. Are they angels? Demons? What is the essential humour that forces them to be in perpetual motion?

I guess the best answer depends on the precise nature of the world you're leaving the statement to, but I would say nothing could be more useful to them then a restatement of the scientific method itself, which could then be used to re-acquire all the lost information:

"All things happen according to certain immutable laws, which can be ascertained by repeated observation/experimentation, then used to make useful predictions."

Seems obvious to us, but very few civilizations ever figured this out.

Well, depending on the kind of world they're trying to come back up in, the formula for black powder and a description of what cannons and muskets look like might be pretty helpful, too. Though the germ theory of disease, and maybe some religious rules regarding the separation of where you crap from where you get your water from, might beat that out.

Yes, this.

I'd expected the Feynman-critical comments to be full of stuff about how it would rather be optimal to formulate the principles underlying the scientific method in a clear, concise manner such as this. Instead I had to scroll down more than 50 comments to even find somebody who thought this might be the optimal way to go. In my opinion people who didn't even consider this approach to the problem probably don't know very much about how humans got to where we are today, and should not be giving advice.

Also, what gwern said.

I think it's just too obvious to us. Either that, or it was assumed he was leaving the comment to scientists. That's the problem with these hypotheticals!

I would grant them the pleasure of figuring things out on their own. Silence.

I would improve on Feynman: Only Universes that are conscious exist. (That's the most profound and important implication of Quantum theory, which is the most fundamental and accurate and far reaching of modern scientific theories and knowledge)
I would never even mention Keynsisn economics, as it is entirely bogus. Rather, I would ignore Keynsianism by saying:
The Invisible Hand is real.
I would combine both in a single statement. The appearance of order out of chaos is the consequence of the consciousness of the universe (the only kind that can exist).

Define "conscious".

Where did you learn physics? I've never heard a physicist claim that the universe is conscious.

I think the quantum mechanics reference that observation seems to play a part in creation of reality.


I'm a physicist myself. I'm familiar with the double slit experiment.

The statement that observation effects the results of an experiment is different from the statement that a conscious observer effects the result of an experiment. It's an even bigger leap to say that it implies that the universe is conscious.

Hi Will, I'm _not_ a physicist - totally failed at my efforts to become one - but I do find the results of this experiment one of the most surprising and counter-intuitive findings in science - based on my admittedly limited exposure. I could the the "one sentence" potentially springing from here.

"In the battle of the sexes, there will never be a final victor, because there's too much fraternizing with the enemy."

Either Henry Kissinger or Will Rodgers

Wow, Lancester does such a nice job in this essay. Does anyone in America write so clearly and so honestly?

(I haven't encountered that person, so please do post if you believe you have an answer)

The second law of thermodynamics and the second welfare theorem.

Second law of thermodynamics, usually phrased as, There ain't no such thing as a free lunch.

I thought it was "You cannot break even." ;-)

"Governments are not households", along with "we borrow in our own currency" has become popular code-speak for the definitively false statement "we do not face a budget constraint (at least as long as my preferred party is in power)". Ironic that this pseudo-economic bunk is coming from the same people who took umbrage at Cheney for making the (also false) claim that "deficits don't matter".

Careful with the Cheney quote. In context, he is saying that deficits don't matter... politically. Which is a pretty accurate statement as far as it goes.

As an economic statement it is fantastically wrong. As a political statement- particularly at its time- it's just about dead on.

Oh, I think that Cheney meant that deficts don't matter economically. He was suggesting that higer deficits do not lead to higer intererst rates -- which is true and flies in the face of conventional wisdom.

Whether it leads to a less efficient allocation of resources is annother matter.

What he really meant was deficits don't matter if Republicans are in control, but once not in control, then deficits are all that matter, as that is the means of regaining power, for balanced budgets make voters hate Democrats.

It was "Reagan showed deficits don't matter", and I've always taken that to mean they don't affect the President's popularity or re-electability.

"He was suggesting that higer deficits do not lead to higer intererst rates — which is true and flies in the face of conventional wisdom."

Somebody tell Greece.

“If you come to the conclusion, as is too often the case, that it is a good thing to break windows, that it causes money to circulate, and that the encouragement of industry in general will be the result of it, you will oblige me to call out, ‘Stop there! your theory is confined to that which is seen; it takes no account of that which is not seen.’”

In the long run we are all dead.

Wait...didn't someone already play this game, in an attempt to torture the backward civilization that found it?!?

In English, we read it as "In the beginning, God created..."

"Throughout keep in mind that 99% of all historic cycles have been “real business cycles,”"

[Citation Needed]

I thought that was meant as a bit of humor -- after all they did actually exists so I assume they were real ;-) but no one ever says 100% because there's always that one exception.

[Citation] Every drought since the agricultural revolution.

How does Paris get fed when no one man or group knows, or can know, what needs to be produced, when to produce or how much to produce?

Of course one could pick a different city or even downgrade to a town.

There is no such thing as a free lunch, and being able to grow your own food doesn't change that.

That's ok. As long as the birth control is free.

If you want an excuse to excercise power, you can make one up.

"It is through exchange that difference becomes a blessing and not a curse."

Jonathan Sacks.

For macro-economics, surely after the debacles of the 20C we have learnt enough so we confidently can tell them to not bother with attempting central planning if they want to have an efficient economy, it's too complex a problem and local optimization by market forces is going to be best.

For economics in general I would say that by definition a voluntary trade always makes you better off, so trading with other countries makes you better off, not worse.

My vote for science, I think it's not original though, is "the sun is a star and the stars are really a long way away"

The most useful thing we could give them though would be the formula for making fertilizer safely from human and animal wast faces.

"Structural deficits matter a lot, but only in the long run; temporary deficits never do."

Science is science, religion is religion, politics is politics, and macroeconomics isn't sure.

The key bit of science is the question "What's your evidence for that?" and the notion of "evidence" that goes with it. God's word isn't a permitted answer.

So, it's not completely clear that "not austerity" would leave people that much better-off, accounting for long-run debt levels. On the other hand, it's clear that central planning has been disastrous, especially in East Asia. Maybe the sentence should be "Don't destroy capital or entrepreneurs".

Well, let's hope if this does happen nobody in MR is asked, seeing as all that will be left is apparently some sort of free market prejudice or ahistorical tripe.

I know of the effect that John Law had in enabling (partially) the French Revolution and a handful of other cases, but is there a good comprehensive survey of sovereign bankruptcy as a historical norm? I would count "A Nation of Deadbeats" as a good first text on "99% of historic cycles/business cycles", but I frequently find confusion about how the present major
sovereigns are creditworthy. People seem to choose "yes" or "no" to answer the question as a sort of Rorshcach test-answer.

Macro in one sentence for posterity: relations between macro variables are not causation relations

Or "macro phenomena are emergent phenomena caused by micro phenomena"

"States are not markets" works as well for me.

for science you really need a pithy summary of the scientific method:

"Come up with a theory, come up with an experiment to try and falsify the theory, and then publish your results to let others review and repeat it"

"By pursuing her own interest, one frequently promotes that of the society more effectually than when she really intends to promote it."

Ah yes, states aren't like households.

It can follow the other leaders of the past:
Tech stocks will rise forever.
Home values will increase forever.

And now interest rates will stay low forever... so debt doesn't matter... right?

Pardon me, I'm not laughing at you; I'm laughing with you... you're just not laughing with me yet.

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