ARLT 100g

Living with Uncertainty

Time: Tuesday/Thursday, 11:00-12:20

Location: VKC 157

Instructor: Kenny Easwaran

Office: STO 227

Office Hours: Friday, 1:00-3:00, or other times if you e-mail for an appointment.

"There are known knowns; there are things we know that we know.

There are known unknowns; that is to say, there are things that we now know we don't know.

But there are also unknown unknowns – there are things we do not know we don't know."

—United States Secretary of Defense, Donald Rumsfeld

Our life is filled with uncertainty, from the grand scale (will unchecked carbon emissions lead to a massive rise in sea levels over the next few decades, or will it be smaller and slower?) to matters of very personal concern (will I need extra medical care in my retirement?) to the mundane (will the movie theater be sold out of tickets this Friday?) And yet somehow, we must live with this uncertainty, and act in spite of not knowing the consequences, both as individuals and as a society. This class will examine various means of dealing with uncertainty that have been proposed by philosophers and statisticians, and compare them to the ways that psychologists say we as humans naturally tend to deal with it. We will question our biases, and think critically about the extent to which certainty is an ideal to strive for, and the ways to deal with not being able to have it, in life, in philosophy, and in science.


Rene Descartes, Discourse on Method

David Hume, Enquiry Concerning Human Understanding

Daniel Kahneman, Thinking Fast and Slow

Nate Silver, The Signal and the Noise

You should purchase the books by Kahneman and Silver. If you don't want to buy them from the university bookstore, they are available as hardcover, paperback, or e-book editions through Amazon and other sites. The books by Descartes and Hume are hundreds of years old and are thus out of copyright. I have linked above to freely available online translations of each of them, but if you prefer to use a different edition, any translation or edition that includes the complete text is acceptable, especially if you prefer to read in hard copy. Hume wrote in English, but he was writing in the 18th century - the link I have provided is a modernized "translation", so if you use a different version, be aware that some of the language may be harder to understand from a modern perspective, since many words have changed their meaning or even spelling, and some grammar has changed as well.

Written Assignments:

In addition to helping you think about the ways we do and should deal with uncertainty, one of the major goals of this class is to help you express yourself clearly and concisely in writing. Thus, there will be short (~1 page) weekly writing assignments due Saturdays at 6 pm (at least for now), and two longer papers (~3-4 pages). Papers will be due approximately on March 15 and May 13. The weekly writing assignments on the weeks leading up to the papers will be replaced by projects contributing to the papers.

All assignments should be sent by e-mail, preferably as an attached .pdf file, to If you don't know how to convert a file to .pdf, ask me. Please include your name and e-mail address at the top of the page.

Grading for the course will be 40% from the weekly assignments, 25% from the midterm paper, 25% from the final paper, and 10% from participation.

Feel free to discuss your writing assignments with each other (or anyone outside the class), and read each other's drafts - this is in fact the most useful way to improve your writing! However, I ask that the actual writing be yours. You should give proper credit for all ideas in the paper. If someone suggested a problem or an argument for you, then thank them! If you found some useful discussion in another source, then say what that source is, whether you directly quoted or merely paraphrased ideas. Giving proper credit to friends, collaborators, and other scholars doesn't diminish the value of your own work, and actually helps make it more valuable.

Note: Wikipedia is not a proper reference, even though it is quite useful. Because of the editing process of Wikipedia, it is not always reliable. However, they have a policy that all information on Wikipedia comes with a citation to some original source - before including ideas from Wikipedia in any of your work, you should always track down the original source (which should be linked or footnoted in the article), and see whether it really says what is claimed. If you can't find the original source, then it's likely that Wikipedia is just wrong about this claim.



Each paper should be approximately 3-4 pages long.

To help you structure the papers, each paper assignment will ask you to write an outline one week, then write the paper the following week, and then give you one more week to rewrite or edit the paper into its final form. The overall set of these assignments will receive one grade together, rather than being graded individually the way that other weekly assignments are.

The outline should look approximately like this:

  • Thesis statement

  • Topic and main point of first section

    • Topic of first paragraph of first section

    • Topic of second paragraph of first section

    • ...

    • (If you will need to cite sources for some of your points, list the relevant book and chapters here.)

  • Topic and main point of second section

    • Topic of first paragraph of section section

    • Topic of second paragraph of second section

    • ...

    • (If you will need to cite sources for some of your points, list the relevant book and chapters here.)

  • Topic and main point of third section

    • Topic of first paragraph of third section

    • Topic of second paragraph of third section

    • ...

    • (If you will need to cite sources for some of your points, list the relevant book and chapters here.)

Each of these bullet points might be written as a sentence that could be included directly into the paper, but they could also be a general description of the topic of the relevant paragraph or section if that seems more useful for organizing your thoughts.

The point of writing the outline is to help you think about the big picture first - what are all the points you are going to make? how do they fit together? how would a change in one of those points affect the support it gives to my thesis, and thus make me change the thesis?

When it comes time to write the paper, you can then expand each section as you go along. You may be able to use the topic sentences you've written down as the first sentence of each paragraph of the paper. You might give section headings for the sections of the paper if you think that is helpful, or you might just have some transition in the text at the end of the last paragraph of a section to indicate that you are about to start talking about a new topic.

The first and last paragraph or so of the paper are special. Their point is to summarize the paper, so that a reader can clearly understand what they are about to read or what they did read. The introductory paragraph is likely to begin with a mention of the topic your paper is about, then mention the topics of the sections of the paper, and then build to a statement of the thesis of your paper. The concluding paragraph is likely to begin with a reminder of the thesis of your paper, then make the main subpoints that you want the reader to have taken away from the parts of the paper, and perhaps say something about why this is important for the topic under consideration.

Paper 1 Topics

Topic A

Write a paper about what role certainty plays for Descartes.

In some parts of the discourse, Descartes says that you should only believe something if it is absolutely certain; in other parts he says you should believe some things even if you're somewhat uncertain of them.

Your main thesis should be an overall claim about the importance of certainty to Descartes.

A suggested structure is the following. After the introduction, begin by summarizing the two sorts of claims he makes (using appropriate quotations from the reading) and explaining the tension between them. Then show how your proposal for Descartes' view of certainty is able to explain each of these two sets of claims, given the different context where he is discussing them. Then, if you want, you might say something more general about how this view of certainty sheds light on some other issue (perhaps one that we have discussed in class). Finally, there should be a conclusion paragraph summarizing the paper.

Topic B

Write a paper using ideas from Kahneman to explain a common mistake in forecasting that Silver discusses.

Your main thesis statement should mention a specific cognitive effect that Kahneman discusses (for instance, priming, availability, etc.), mention a particular mistake that comes up in one of the domains Silver discusses (for instance, "wet bias" or overfitting or something else), and state that the effect explains the mistake.

A suggested structure is the following. After the introduction, explain the mistake that Silver discusses, stating both what the mistaken prediction is people make, and why we should think of it as a mistake. (This may involve giving some background information about the situation, which can either involve quotations from Silver or from other sources.) Then you should discuss the effect that you will eventually use to explain it - here you will give some citations to Kahneman in order to explain how the effect works, and probably something about why it is often a useful heuristic even though it sometimes leads to biases in our judgment. (Make sure to define every term that comes up, including the name of the effect you mention, but also terms like "system 1" and "system 2", or any other psychological concept you mention in passing.) Then you should show how this effect can be used to explain the mistaken prediction mentioned earlier (and perhaps make a broader claim about how this affects our lives in some way). Finally, there should be a conclusion paragraph summarizing the paper.

Paper 2 Topics:

Topic A

Write a paper comparing Alison Gopnik's view of babies as scientists ("Finding our Inner Scientist") to the less-rational view of adults that Kahneman discusses.

Your main thesis statement should state the relationship between these views of the mind. (e.g., "although children are good at dealing with new evidence, these skills are lost in adulthood", or "the irrational biases Kahneman notices can be surprisingly rational in simple scenarios", or "the abilities Gopnik recognizes in children give rise to mistakes in adulthood", or something parallel.)

A suggested structure is the following. After the introduction, summarize Gopnik's view of children as effective scientists, including a brief discussion of some evidence for her claim. Summarize some example of a bias that Kahneman talks about, including some evidence for his claim, as well as a discussion of why it is irrational. Explain how the relation between these effects supports your thesis. Finally, there should be a conclusion paragraph summarizing the main points of the paper.

Topic B

Write a paper explaining how we should react to published scientific findings in light of the paper, "Why Most Published Research Findings are False", by John Ioannidis.

Your main thesis statement should state the overall reaction we should have to a new finding (should we accept it? ignore it? treat it as slight evidence? treat it as strong evidence?)

A suggested structure is the following. After the introduction, explain at least one argument by Ioannidis, to show why we should expect most research findings to be false. Then you should give a basic explanation of the Bayesian method of responding to evidence (starting with a prior probability, and modifying it in light of the probability that you would get this evidence if one hypothesis were true, compared to the probability that you would get this evidence if a different hypothesis were true). Then you should show how this method supports your claim about the overall reaction we should have to the evidence that a research finding has been published. Finally, there should be a conclusion paragraph summarizing the points of the paper.

You may find it helpful to choose a representative research finding to use as an example throughout - perhaps an interesting report you read about in the health or science section of the newspaper recently, or an imaginary study that claims to find a health benefit or cost to some sort of food.

(You may want to switch the order of the first two sections, if you think it would be useful to discuss Bayesian methods before explaining the argument from Ioannidis.)

Topic C

Write a paper explaining how David Hume would react to some modern scenario. This could be evidence of climate change, failed predictions in the housing market or in politics, evidence of some strange happening like the disappearance of flight MH 370, or something else. (In each case, you'll want to focus on one very specific claim about this modern scenario, rather than the whole thing generally.)

Your main thesis statement should state what you think Hume's view would be - should we believe some particular version of the facts? should we be skeptical of some claim? should we incline towards some view while remaining uncertain?

A suggested structure is the following. After the introduction, you should describe the modern scenario you are discussing, and focus on one specific aspect, including any relevant evidence and citations. In the next section, you should summarize the relevant points from Hume (including a few relevant quotations). Depending on your scenario, this may primarily involve issues from chapter 5 about using cause and effect to generalize from the past into the future, or chapter 10 about believing the testimony of others about miracles, or some other chapter. The third section should explain how Hume's ideas are relevant to the modern scenario, and support your thesis. Finally, there should be a conclusion summarizing the main points of the paper.

Academic integrity:

All students are expected to understand and abide by these principles. SCampus, the Student Guidebook, contains the Student Conduct Code in Section 11.00, while the recommended sanctions are located in Appendix A (.pdf file). Students will be referred to the Office of Student Judicial Affairs and Community Standards for further review, should there be any suspicion of academic dishonesty. The Review process can be found in Section 13.00.

Statement for students with disabilities:

Any student requesting academic accommodations based on a disability is required to register with Disability Services and Programs (DSP) each semester. A letter of verification for approved accommodations can be obtained from DSP. Please be sure the letter is delivered to me as early in the semester as possible. DSP is located in STU 301 and is open 8:30 a.m. to 5:00 p.m., Monday through Friday. The phone number for DSP is (213) 740-0776.


Why study philosophy?

Stanford Encyclopedia of Philosophy

Eliezer Yudkowsky, Harry Potter and the Methods of Rationality (a possibly entertaining discussion of many of the concepts we'll be discussing, if fan-fiction is your type of thing)


(Readings and writing assignments for future weeks are subject to change.)

Jan. 14, 16


Hume, Section 1 (before Tuesday, Jan. 14)

Kahneman, Chapters 1, 2 (before Thursday, Jan. 16)


A demonstration of the add-n task Kahneman describes

Video of the selective attention test

Writing assignment (due Saturday, Jan. 18, at 6 pm, as a .pdf, to

Write one page explaining the distinction between System 1 and System 2, summarizing ideas from the Kahneman book and our in-class discussion. Make sure to include an explanation of a simple test to figure out whether a task belongs to System 1 or System 2, and say something about how the ideas explain why we shouldn't talk on the phone while driving.

Jan. 21, 23


Kahneman, Chapter 4, Chapter 6

Hume, Section 3


An example of a magic trick involving priming.

An article discussing the fraud behind many of the priming experiments we are discussing.

A video demonstrating perception of causation.

The Arizona school study, with data.

Writing assignment (due Saturday, Jan. 25, at 6 pm, as a .pdf, to

Political polls often ask multiple questions. Sometimes the order of the questions matters. For instance, in December 2008 (after Obama was elected but before he was sworn in, while the Global Financial Crisis was in the middle of taking place), Pew asked people how satisfied they were with how things were going in the US at the time. Half of them were then asked their opinion of how President Bush was doing at his job, while the other half were asked about his job approval first:

Write approximately a page explaining why a substantially larger number of people were dissatisfied with how things were going when they were first asked about their approval of the current president. Use the concept of priming to explain this, or else explain why you think that priming is not relevant. Write as if for a general educated audience that hasn't been doing our reading.

Jan. 28, 30


Silver, Chapter 4

Writing assignment (due Saturday, Feb. 1, at 6 pm, as a .pdf, to

Write about a page on the following topic. Explain (in very simple terms) how "persistence" and "climatology" can be used to forecast the weather for tomorrow. Explain very briefly the difference between these purely statistical forecast methods and the general idea of a forecast based on a model. (You shouldn't need to say anything about how the model actually works.) Say why persistence and climatology are useful baselines for measuring the value of a model, even if they are not especially good as forecasts.

Feb. 4, 6


Kahneman, Chapter 10

Descartes, Sections 1, 2

Writing assignment (due Monday, Feb. 10, at 11:59 pm, as a .pdf, to

Look at the data about bicycle commuting contained in this report by the League of American Bicyclists, made using census data. Write approximately a page explaining why the following argument is bad:

Among cities of over 1,000,000 people, Philadelphia has the highest bike commute rate at 2.3%.

Among cities of over 300,000 people, Portland has the highest bike commute rate, at 6.1%.

Among cities of over 200,000 people, Madison has the highest bike commute rate, at 6.23%.

Among cities of over 100,000 people, Boulder has the highest bike commute rate, at 12.1%.

Among cities of over 50,000 people, Davis has the highest bike commute rate, at 19.1%.

Since the bike commute rate goes up as the population goes down, smaller cities must be better for bike commuting than larger cities.

In explaining what is wrong with this, you may want to explain the phenomenon Kahneman calls "the law of small numbers". You shouldn't have to do any actual statistical analysis to show why this argument shouldn't be convincing.

If you want to additionally argue that the claim is false (or give a better argument for why it's true - I haven't checked whether it's true or false), there may be some simple facts from this report you can use, though if you do, you should be careful to make sure that the facts you use aren't vulnerable to the same flaw. Also, you shouldn't use facts from outside this report in your argument unless you have a citation for them - people make a lot of errors in thinking about what factors are actually good or bad for this.

Feb. 13 (I will be out of town on Feb. 11, so there will be no class that day)


Descartes, Sections 3-6 (finish the book)

Writing assignment (due Saturday, Feb. 15, at 6 pm, as a .pdf, to

Write approximately a page on the following prompt. In Part V, Descartes gives an argument that animals have no souls, but that humans do have souls. Summarize his argument (using appropriate quotations from the reading if needed, but only a few), making explicit the features of human and animal behavior that are important to his argument. Explain why one of these premises is false. You can use some facts that are obvious to modern readers that wouldn't have been obvious to Descartes, perhaps involving modern technology, but don't try to go too deep into the science, unless you have some particular expertise.

Feb. 18, 20


Kahneman, Chapters 11, 12, 13

Supplementary (optional) reading:

Paul Slovic, "Trust, Emotion, Sex, Politics, and Science: Surveying the Risk-Assessment Battlefield"

Writing assignment (due Saturday, Feb. 22, at 6 pm, as a .pdf, to

In one page, describe the phenomenon of anchoring and explain three different ways that it can come about. Be sure to be clear about how the three different explanations are distinct, even though a single case might be influenced by multiple of them.

Feb. 25, 27


Silver, Chapter 5

Writing assignment (due Saturday, March 1, at 6 pm, as a .pdf, to

Outline for paper 1 (see earlier section on "Papers" for proposed topics and description of outlines)

Mar. 4, 6


Hume, Section 4, Parts 1 and 2

Hume, Section 5, Part 1

Writing assignment:

Draft of paper 1 due

Mar. 11, 13


Kahneman, Chapters 17, 18

Writing assignment:

SUNDAY MARCH 16 - PAPER 1 DUE - note changed date

March 17-22 Spring Break

Mar. 25, 27


Kahneman, Chapters 20, 21, 22

Supplementary (optional) reading:

Implicit Association Test

Isaiah Berlin, "The Hedgehog and the Fox" (the first few pages are all that is relevant, unless you are interested in Tolstoy and the philosophy of history)

Atul Gawande, "The Checklist"

Writing assignment (due Tuesday, April 1, at 11:59 pm as a .pdf to

Write approximately a page explaining the conditions that make a task a good one for human expertise and the conditions that make a task a bad one for human expertise. Give an example of each sort of task (bonus points if they're not from the book, and they are accurate) and explain why the do or don't fit these conditions.

Apr. 3 (I will be out of town on April 1, so there will be no class on that day)


Silver, Chapter 2

Alison Gopnik, "Finding our Inner Scientist"

Writing assignment:

None - my apologies for not having posted that earlier.

Apr. 8, 10


Hume, Section 6

Silver, Chapter 8

Supplementary optional reading:

John Ioannidis, "Why Most Published Research Findings are False"

Chris Anderson, "The End of Theory: The Data Deluge Makes the Scientific Method Obsolete"

Writing assignment (due Saturday, April 12, at 6 pm, as a .pdf, to

Write approximately a page explaining similarities and differences between the concepts of objective chance and subjective probability. Make sure to say why we can have subjective probabilities in some situation even when we think there are no objective chances.

Apr. 15 (I will be out of town on April 17, so there will be no class on that day)


Silver, Chapter 1

Writing assignment:


Apr. 22, 24


Hume, Section 10

Lawrence Shapiro, "A Drop in the Sea"

Writing assignment (due Saturday, April 26, at 6 pm, as a .pdf, to

Write approximately a page about believing in miracles. You should explain Hume's definition of a miracle, give at least one reason that he suggests we shouldn't believe in miracles, and also say something about a condition that could get around his argument so that we should believe in what is apparently a miracle.

Apr. 29, May 1


Silver, Chapter 12

Writing assignment (due 11:59 pm, Monday, May 5, as a .pdf, to

Outline for paper 2 (see earlier section on "Papers" for proposed topics and description of outlines)

I will return comments on the outlines by Wednesday, May 7. After receiving these comments, you may submit a second version of the outline, or a rough draft of the paper, to get extra comments on it, but I may take a day or two to get these comments back to you. This second outline or rough draft is not mandatory.

MAY 15 - PAPER 2 DUE by 11:59 pm