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Potato paradox

en.wikipedia.org

11–20 of 142 posts

Re: Potato paradox

#11
post #5

A much more important example of this than "martian potatoes" is uranium enrichment. Natural uranium is ~1% U235; bombs need 90+% U235. So when you've enriched it from 1% to 2% it doesn't seem like you've made a lot of progress towards 90. If instead of enriching U235 you think of it as eliminating U238, though, then you've done half of the work.

Thanks for pointing this out. I've vaguely heard before that some nations (like North Korea) have difficulty building nuclear bombs because it's hard to enrich Uranium. This really quantifies that difficulty for me.

Re: Potato paradox

#12

Why is this a "paradox"? Not sure what this applies to either. It's not even counterintuitive.

There is a certain type of mind that delights in paradoxes, to the extent that even after an explanation has been clearly produced, the person will continue to insist there is a paradox.

Naming things paradoxes attracts this sort of individual, so it's a kind of marketing ploy for an idea: it won't just get it talked about, it'll get it talked about forever, because each generation of paradox-mongers will take it up anew and discuss it and analyze it and do absolutely anything except acknowledge that the specific flaw in the reasoning that leads to the appearance of an impossible conclusion being true was exposed generations ago.

For example, consider the supposed paradox of the evening star and morning star, which I will first state in the a way that makes it clear there is no paradox, then restate in the traditional way.

"The Evening Star is Venus seen in the evening sky." "The Morning Star is Venus seen in the morning sky." "Transitivity implies therefore that the Evening Star is the Morning Star, since Venus seen in the evening sky is Venus seen in the morning sky."

This is obviously stupid: no one would make this claim. The traditional formulation actually depends on a falsehood, or at least on radically incomplete statements:

"The Evening Star is the planet Venus." "The Morning Star is the planet Venus." "Transitivity implies therefore that the Evening Star is the Morning Star, since the planet Venus is the planet Venus."

At this point, you can spend millions of words explaining why the statements identifying lights in the sky viewed at a particular time of day with a ball of rock orbiting the sun are problematic. It will be pointless: paradox-mongers will simply not let their nice toy be demolished.

Most traditional paradoxes have straightforward resolutions (frequently involving inserting a knowing subject into them, like the person who observes Venus) but none of them will ever be "solved" because of this purely psychological resistance to the possibility of their solution on the part of a very vocal sub-population.

One useful trick is to never let a paradox be stated in the traditional way. The first step in any discussion should be to restate the paradoxical situation as completely as possible, usually by introducing the perspective of particular individuals, as I've done above. Traditional paradoxes almost all depend on very specific ways of stating them for their psychological effect, and breaking out of that ritual pattern of restatement often makes them look simply stupid. One can then ask what is missing in the ritual statement of the paradox that makes it not seem stupid.

In the case of the Potato Paradox, the restatements we've seen here, which introduce the ratio 1:99 as the way to think about the problem, is a good example of this. Since the answer is not intuitive, the correct way to introduce the problem is to make it intuitive, not to blurt out a non-intuitive answer and expect the now-confused listener to catch up. That's just bad pedagogy.

Re: Potato paradox

#13

The thing the article doesn't point out is why it seems unintuitive. If you phrased the question as "You have N pounds of potatoes", or with a specific number other than 100, it would come across as less unintuitive. As you read, you see "100 lbs", and "99%", so percents and potato components are both out of 100. So then you see 98%, which is 98/100...

Although it's somewhat true, if you had started with 14 pounds of potatoes instead, I still think most people at first glance would expect the final weight to be around 14, not half of it.

Re: Potato paradox

#15
post #9

Why is this a "paradox"? Not sure what this applies to either. It's not even counterintuitive.

As stated in the article, this is an example of a veridical paradox under Quine's classification of paradoxes. Which, a quick link following reveals as… A veridical paradox produces a result that appears absurd but is demonstrated to be true nevertheless. Amazing what philosophers will get up to.

The point is that it doesn't even appear absurd unless you have absolutely no number sense.

Re: Potato paradox

#16
This is only confusing because of the potatoes.

If you said you had a pool that was 99% water, that changed to 98% water, the massive weight drop would be much less surprising.

Re: Potato paradox

#17
post #13

The thing the article doesn't point out is why it seems unintuitive. If you phrased the question as "You have N pounds of potatoes", or with a specific number other than 100, it would come across as less unintuitive. As you read, you see "100 lbs", and "99%", so percents and potato components are both out of 100. So then you see 98%, which is 98/100...

Although it's somewhat true, if you had started with 14 pounds of potatoes instead, I still think most people at first glance would expect the final weight to be around 14, not half of it.

I agree, but I suspect fewer people would make the mistake. Partly because more people would actually do the math, and partly because there's no immediately attractive wrong answer involving "98/100" and "100 lbs". There's still a somewhat attractive wrong answer of multiplying 98/100 by 14 lbs, but there's one less reason to make that mistake.

This seems like the kind of thing that could be tested with a study. Ask a few hundred people each version of the problem (ideally filtering out anyone who has seen the problem before), and see how many get each version right.

(Potato paradox problem paradox: You ask 100 people to solve the potato paradox. 99% of them get the answer wrong. You drop people who answered incorrectly until you have a group where 98% got the answer wrong. How many people are left?)

Re: Potato paradox

#18

Neat. This bumps up my list of food-related maths from 3 to 4. So far: https://en.wikipedia.org/wiki/Ham_sandwich_theorem https://en.wikipedia.org/wiki/Pizza_theorem https://en.wikipedia.org/wiki/Layer_cake_representation

You can add https://en.wikipedia.org/wiki/Pancake_sorting

And https://en.wikipedia.org/wiki/Fair_cake-cutting

Re: Potato paradox

#19
This strikes me as similar to the non-intuitiveness of compounding interest (and related brain teasers like "bacteria doubling population every day" and "pieces of gold doubling on a chess board").

Re: Potato paradox

#20

Earlier quoted context omitted.

You can add https://en.wikipedia.org/wiki/Pancake_sorting

And https://en.wikipedia.org/wiki/Fair_cake-cutting

I guess mine is sort of an anti-food-related math concept, then! https://en.wikipedia.org/wiki/No_free_lunch_theorem
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