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August 31st, 2023 (Permalink)

The Old Newspeak & the New Newspeak

Notes:

  1. Jared Downing, Priscilla DeGregory & Jorge Fitz-Gibbon, "Politicians, prosecutors dropping the ball on booming NYC sex trade: advocates", The New York Post, 8/8/2023.
  2. See, for instance: Teo Bugbee, "‘Kokomo City’ Review: Dispatches From the Down Low", The New York Times, 7/27/2023.
  3. Doublespeak Headline, 8/3/2008.
  4. Frédérique Delacoste & Priscilla Alexander, editors, Sex Work: Writings by Women in the Sex Industry (2nd Edition, 1998).
  5. "Sex Work, Sex Worker", Google Books Ngram Viewer, accessed: 8/31/2023.
  6. Close Encounters with Doublespeak of the Third Kind, 9/8/2019.
  7. Anemona Hartocollis, "Colleges Celebrate Diversity With Separate Commencements", The New York Times, 6/2/2017.
  8. George Orwell, Nineteen Eighty-Four (1949), Part I, Chapter 1.

Disclaimer: I don't necessarily agree with everything in these articles, but I think they're worth reading as a whole. In abridging them, I have sometimes changed the paragraphing of the excerpts.

August 14th, 2023 (Permalink)

How to Solve a Problem: Backtracking1

As usual in these entries on problem-solving, let's start out with a puzzle.

Puzzle: A Delivery Dilemma

If you work delivering packages nowadays, you are expected to deliver a diverse assortment of items to the same address. For instance, suppose that you are tasked with delivering to a house on top of a high hill. Unfortunately, no one is home so that you'll have to leave the packages on the porch of the house. The road ends at the bottom of the hill, and the only way to get to the porch is a steep and narrow footpath up the side of the hill. Suppose, further, that you are to deliver a live goat, a hungry dog, and a pizza. Because of the steepness of the hill, you can only take up one item at a time, so it will require at least three trips to deliver all three to the porch. That's a lot of climbing! However, you can't leave the goat and the pizza alone together in the delivery van or on the porch, because the goat would eat the pizza. Similarly, you can't leave the hungry dog alone with the goat, since the dog would attack the goat. Luckily, you can leave the dog alone with the pizza, since everyone knows that dogs don't like pizza.

How can you get all three items alive and intact to the porch? What is the minimum number of trips up and down the steep hill that you will have to make?2

This puzzle looks like a prime candidate for hill-climbing3, and indeed that will play a role in solving it. Since your problem is to get all three items from the base of the hill up to the house on top, you have a clear measure of progress, namely, how many objects are on the porch. So, let's work our way through it.

The first step, of course, is to carry one of the objects up to the house and leave it on the porch, but which one? You can't take the pizza up first, since that would leave the dog and goat alone together in the delivery van. Also, you can't take the dog up first, since that would leave the goat and pizza alone. So, the only alternative left is to take the goat up first, leaving the dog and the pizza in the van4. So far, so good.

However, now you're stuck. You can't take the dog up and leave it on the porch alone with the goat since the dog will attack the goat, and you can't take the pizza up and leave it on the porch because the goat will eat it. The puzzle appears to be insoluble! In fact, it is impossible to solve if you stick to hill-climbing.

To solve the puzzle, you must backtrack, which is the topic of this entry. Here's how to do it: take the dog or the pizza―it doesn't matter which―up to the porch and leave it, then take the goat back down to the van! This step goes against common sense, which is what makes the puzzle hard. It also violates the hill-climbing algorithm, since all you've done is switch one object on the porch for another. The hill-climbing algorithm tells you to always take an action that increases the number of items delivered, but you can't do so and solve the puzzle.

To continue the solution: you return to the van with the goat, leave it in the van, and take the pizza or dog, as the case may be, up the hill. You can safely leave the dog and pizza together on the porch as you return to the van for the goat. Finally, you take the goat back up and place it on the porch. It took four trips up and down the hill to deliver the three items!5

Hill-climbing alone is usually not enough to solve a problem. Instead, you need to combine it with backtracking, that is, when you get stuck and can't seem to make further progress towards the goal, backtrack to an earlier stage and take a different route. For instance, in trip-planning, we often use hill-climbing by choosing among routes that lead in the general direction of where we want to go. However, sometimes the shortest route to a destination may require that you backtrack to gain access to it, or it may take a road that sometimes heads in the wrong direction.

In the above puzzle, you must backtrack because you have two different goals that sometimes conflict: one goal is to get all three items on the porch―and if this was your only goal you could accomplish it with hill-climbing alone―but your other goal is to deliver the items undamaged, and for that you have to backtrack.

In the previous entry, I mentioned three different obstacles faced by hill-climbing: plateaus, ridges, and multiple peaks. If, in the course of hill-climbing, you get stuck on any of these obstacles, then backtracking will be necessary in order to get off. The above puzzle is a different type of obstacle―namely, a detour6―which comes about when you have more than just the goal of getting to the top of the hill. When you have more than one goal, you will often need to backtrack in order to accomplish all of them.

Now that you have another problem-solving tool in your kit, try the following puzzle for practice. Note that this puzzle takes place in a world of wizards and little people where magic is real, but you won't need magic to solve it.

Puzzle: To the Far Shore

The Great Gray Mage and his two traveling companions, both halflings, needed to cross a bottomless and nameless river. They dared not swim it for fear of monsters rising from its murky depths. The mage's magic was losing its power, and the three were on a quest to discover why. Luckily, there was a small rowboat pulled up on the bank that the three could borrow to make the crossing. However, the boat was of a size that could not hold all three travelers at the same time since it could carry only the weight of the mage without sinking. Of course, the halflings each weighed half as much as the mage so the boat could carry both across. If the mage rowed the boat across the river, the halflings would be left behind; and if the halflings rowed across, then the mage would be left. The mage's powers were so weak that he could not use them to draw the empty boat back across the river, and it appeared that only one crossing could be made. How did the Great Gray Mage get himself and the two halflings across the river without using magic?7

Notes:

  1. For previous entries in this series, see:
    1. Contraction, 4/6/2023
    2. Think Backwards, 5/5/2023
    3. Solving a Problem by Elimination, 6/20/2023
    4. Climbing Up that Hill, 7/5/2023
  2. This is a version of a puzzle that goes all the way back to Alcuin in the eighth century. It's usually presented as the story of a farmer who buys a cabbage, goat, and wolf (?) at a market, and has to cross a river in a small boat that holds only one of the three items at a time. See: Marcel Danesi, The Puzzle Instinct: The Meaning of Puzzles in Human Life (2002), pp. 153-155.
  3. See: Climbing Up that Hill, 7/5/2023.
  4. Notice that we solved the sub-problem of which object to deliver first by elimination; see: Solving a Problem by Elimination, 6/20/2023.
  5. You might wonder what happens to the three items after you leave them on the porch, but that's not your problem!
  6. Wayne A. Wickelgren, How to Solve Problems: Elements of a Theory of Problems and Problem Solving (1974), pp. 85-88.
  7. This is a simplified version of another classic puzzle from Alcuin: as it's usually presented there are two adults and two children, but the solution simply repeats twice the process for getting one adult across the river. See: William Harston, A Brief History of Puzzles: Baffling Brainteasers from the Sphinx to Sudoku (2019), Puzzle 2.
New Book
August 9th, 2023 (Permalink)

Everybody's Somebody's Fool

Quote: "It can be tempting when learning about a simple con to think that you would never have fallen for it―or to assume that only less intelligent, less educated, or more gullible people can be victimized. But the fact is that everyone can be fooled, even the best and brightest among us. In this book, we reveal how people exploit our bias for truth―our inclination to accept too much and check too little―and we propose concrete steps we can take to bolster our defenses. We don't offer a compendium of scams and scammers or a treatise on the history, economics, or sociology of deceit. We also don't delve into the motivations, incentives, and emotional makeup of con artists and their victims. Rather, we explain the cognitive psychology of the cheated―the patterns of thinking and reasoning that make us all vulnerable."1

Title: Nobody's Fool

Subtitle: Why We Get Taken In and What We Can Do about It

Comment: As far as I can tell, not having read this book yet, its subject is how and why people are fooled, but the examples seem to be taken from con games and scam artists, rather than the more controversial politicians and religious charlatans. For instance, the "Introduction" begins by discussing the case of Elizabeth Holmes, the woman behind Theranos who recently began serving a prison sentence2 .

Authors: Daniel Simons & Christopher Chabris3

Comment: Both authors are psychologists and I read their previous book, The Invisible Gorilla4, over a decade ago.

Date: 2023

Card Trick: Before we get on with the new book, let's take a break for a magic trick. Check out the cards below; pick one, any one you want, then concentrate on it. Focus your attention and memorize your selected card so that you'll recognize it again. When you've finished, click on the "Read my mind!" button below it, and prepare to be amazed.

Your chosen card vanished! How did I do that? Did I read your mind and predict the future? See below for an explanation of how the trick works.

Summary: After an Introduction, the book is divided into two parts of four chapters each, followed by a Conclusion. The first part covers four habits; here's how the authors describe them:

We begin with chapters on four key cognitive habits that we all have, crucial features of how we think and reason that unfortunately can be weaponized by people who want to fool us. They include our ability to focus on the information we care about…while ignoring distractions or irrelevant information. With experience, we develop expectations for what should happen or what incoming information should look like, and we use these expectations to automatically make predictions that are accurate much of the time. Our abilities to think and reason depend on our making fundamental assumptions about ourselves, other people, and the world around us; when these assumptions are strong enough, they constitute commitments that we rarely question or even realize we are making. And as we become practiced at any task, we increase our efficiency, meaning we develop routines, rules of thumb, and shortcuts that save us immense amounts of time and effort in making decisions.5

And here's how the authors describe the second part:

The remaining chapters explore four hooks: features of the information we encounter in our daily lives that we find attractive but that can snare us. … When the information we encounter matches or resembles what we already know and trust, we use familiarity as a signal of its truth. We rely on the consistency of information we encounter as evidence of its veracity. We associate great precision in predictions or evidence with the accuracy and truthfulness of the ideas that gave rise to them. And we are attracted to stories of potency, in which small causes have large consequences for our lives and society as a whole.6

The Blurbs: The book has positive blurbs from Annie Duke, Apollo Robbins, and Philip Tetlock7, among others.

Explanation of the Card Trick: The authors of the book present a version of this old trick8 in chapter one to illustrate how the habit of "focus" can be used to mislead us. The trick uses the principle called "misdirection" by magicians, that is, getting the audience to focus in one place while the funny business is happening elsewhere. If you were surprised that your card disappeared, it's because you focused your attention on the card you chose, as I asked you to do, rather than the other four cards. When you clicked on the button, four cards appeared and you looked for your chosen card, but it had disappeared. What you didn't notice is that all of the five original cards had disappeared and been replaced by similar looking ones, so of course the card you chose was not there. If you don't believe me, use the back button on your browser to look at the original row of five cards and compare them.

You can try this trick on a friend or family member by using nine court cards from a deck of cards. Separate them into two packets, one of five cards and the other of four. Have your audience mentally select one card from the five card packet. Now, the hard part of the trick will be to switch the initial five cards for the other four without it being obvious. One way to do so would be as follows: after your audience has mentally selected a card, put the packet behind your back and tell the audience that you're going to remove one card and put it in your pocket. Instead, switch the packet of five cards for the four-card packet, which you placed in your back pocket before the trick began. Then, produce the four cards and ask the audience if the chosen card is there; it won't be. Take a bow.

Disclaimer: I haven't read this book yet, so can't review or recommend it, but its topic interests me and may also interest my readers. Also, the above remarks are based only on reading a sample of the book.

Notes:

  1. "Introduction", p. 3.
  2. "Elizabeth Holmes enters Texas prison to begin 11-year sentence for notorious blood-testing hoax", The Associated Press, 5/30/2023.
  3. See: Check it Out, 9/30/2010.
  4. See: Think, don't Blink!, 6/10/2010.
  5. "Introduction", p. 13.
  6. "Introduction", pp. 13-14.
  7. See: The Limits of Expertise, 12/28/2005, Check it Out, 11/6/2006, Check it Out, 3/26/2009.
  8. "Princess Card Trick", Magicpedia, 2/18/2017.

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