## Belief, Desire, and Rational Choice (Spring 2020)

This course is an introduction to formal models of belief, desire, and rational choice. It has roughly three parts. The first introduces the core ideas of Bayesian epistemology, where belief is treated as an attitude that comes in degrees. In the second part, we turn to formal models of desire, drawing on utility theory in economics and value theory in philosophy. We will also look at some connections between rational belief and desire. The third part takes a closer look at expected utility theory, which formalises the intuition that rational agents do what they believe will bring them closer to satisfying their desires.

No prior knowledge of the material is expected. Familiarity with basic propositional logic will be helpful.

Classes consist of a one-hour lecture plus a one-hour tutorial.

### Course organiser

Dr Wolfgang Schwarz (wolfgang.schwarz@ed.ac.uk)

Office hour: Thursday 15:00-16:00 and by appointment

My office is room 6.02, Dugald Stewart Building.

### Course administrator

Ann-Marie Cowe (philinfo@ed.ac.uk)

### Classes

Lecture: Mondays 16:10-17:00, DSB 1.17

Tutorial Group 1: Tuesdays 10:00-10:50, DSB 1.01

Tutorial Group 2: Tuesdays 13:10-14:00, DSB 1.01

### Assessment

The lecture notes for each week contain **exercises**. You should try
to answer all of them and hand in your solutions (on paper, with your student
number at the top) at the start of the next lecture. I will mark your
submissions for each week on a scale from roughly 30 to 90; the average of
your scores will be converted into 50% of your final grade.

**The question mark rule:** If you write a question mark next to
an answer on an exercise sheet (even if the answer is empty), I will
give you a 20% higher mark if you're wrong and a 20% lower mark if
you're right.

The lecture notes also contain **essay** questions. At the end
of the term, you should choose one of these to write a short essay of
1500 words. Your mark for the essay determines the other 50% of your
grade. The essay deadline is 23rd April, 12pm.

Covit-19 Update: Your final mark is the average of your exercise marks for weeks 1 through 8. You do not need to hand in any more exercises (including those for chapter 9). You do not need to write an essay.

**Check you marks by entering your student number here (including the 's'):**

The marks will be sent to your student email address.

### Readings

The only compulsory reading are the **lecture notes, which you can find here**.

Supplementary reading for the whole course:

- Jonathan Weisberg: Odds and Ends (2019)
- Lara Buchak: "Decision Theory" (2016)
- Katie Steele and H. Orri Stefansson: "Decision Theory" (2015)
- Michael Strevens: Notes on Bayesian Confirmation Theory (2017)

### Literature access

The syllabus below contains pointers to further texts that you are encouraged to read. If a text is not freely available online, you can find it in a secret folder. If you've forgotten the address of that folder, send me an email.

## Syllabus

### Week 1: Overview

How beliefs and desires are related to choice; why beliefs and desires are graded; the difference between conceptual analysis and model-building.

Reading: Chapter 1 of the lecture notes.

Background reading:

- Alan Hajek: "Pascal's wager" (2017)
- Ansgar Beckermann: "Is there a problem about intentionality?" (1996)
- Alisa Bukolich: How scientific models can explain (2011)
- Mark Colyvan: Idealisations in normative models (2013)

### Week 2: Belief as probability

Basic rules of probability; Bayes' theorem; some applications.

Reading: Chapter 2 of the lecture notes.

Background reading:

- Ian Hacking: An Introduction to Probability and Inductive Logic, ch.s 3-7 (2001)
- Jonathan Weisberg: Odds and Ends, ch.s 5-9 (2019)
- Brian Skyrms: "Zeno's paradox of measure" (1983)
- Robert Stalnaker: "The problem of logical omniscience I" (1991)

### Week 3: Probabilism

Why degrees of beliefs should conform to the principles of probability theory.

Reading: Chapter 3 of the lecture notes.

Background reading:

- Alan Hajek: "Dutch Book Arguments" (2008)
- Susan Vineberg: "Dutch Book Arguments" (2016)
- Peter Fishburn: "The Axioms of Subjective Probability" (1986)

### Week 4: Further constraints on rational belief

Belief and perception; conditionalization; the Principle of Indifference; probability coordination.

Reading: Chapter 4 of the lecture notes.

Background reading:

- Ian Hacking: An Introduction to Probability and Inductive Logic (2001)
- Christopher Meacham: "Impermissive Bayesianism" (2014)
- Nick Bostrom: "The Doomsday Argument, Adam & Eve, UN++, and Quantum Joe" (2001)

### Week 5: Utility

Two conceptions of utility; sources of utility; utility and credence; the formal structure of utility.

Reading: Chapter 5 of the lecture notes.

Background reading:

- Simon Blackburn: "Game Theory and Rational Choice", chapter 6 of
*Ruling Passions*(1998) - John Broome: "Utility" (1991)

### Week 6: Preference

The ordinalist challenge; deriving utility measures from a preference ordering.

Reading: Chapter 6 of the lecture notes.

Background reading:

- Samir Okasha: "On the Interpretation of Decision Theory" (2016)
- Daniel Hausman: "Mistakes about Preferences in the Social Sciences" (2011)
- Peter Fishburn: "Utility and Subjective Probability" (1994)

### Week 7: Separability

The composition of value; additivity; discounting.

Reading: Chapter 7 of the lecture notes.

Background reading:

- Paul Weirich: "Multi-Attribute Approaches to Risk" (2012)
- Johanna Thoma: "Temptation and preference-based instrumental rationality" (2018)
- John Broome: "Utilitarianism and Expected Utility" (1987)

### Week 8: Risk

Why maximize expected utility? MEU and risk; localism.

Reading: Chapter 8 of the lecture notes.

Background reading:

- James Dreier: "Rational Preference: Decision Theory as a Theory of Practical Rationality" (1996)
- Paul Weirich: "Expected Utility and Risk" (1986)
- Lara Buchak: "Redescription" (2014)

### Week 9: Evidential and Causal Decision Theory

Newcomb's problem; EDT vs CDT.

Reading: Chapter 9 of the lecture notes.

Background reading:

- Arif Ahmed: Introduction to
*Newcomb's Problem*(2018) - Jack Spencer and Ian Wells: "Why Take Both Boxes?" (2017)
- David Lewis: "Causal Decision Theory" (1981)
- Frank Arntzenius: "No Regrets, or: Edith Piaf Revamps Decision Theory" (2008).

### Week 10: Game theory

Reading: Chapter 10 of the lecture notes.

Background reading:

- Brian Weatherson:
*Lecture Notes on Decision Theory*, ch.s 19-27 (2015) - Philip Pettit and Robert Sugden: "The Backward Induction Paradox" (1989)
- Brian Skyrms: "Game Theory, Rationality and Evolution of the Social Contract" (2000)

### Week 11: Bounded rationality

Reading: Chapter 11 of the lecture notes.

Background reading:

- Samuel Gershman et al: "Computational rationality: A converging paradigm for intelligence in brains, minds, and machines" (2015)
- Daniel Kahneman: "A Perspective on Judgment and Choice: Mapping Bounded Rationality" (2003)
- Saemus Bradley: "Imprecise Probabilities" (2014)