Philosophy 12: Logic and Decision Makingmechanism.ucsd.edu/~mitch/teaching/s11/phil12/lectures/Phil12_S11... · Philosophy 12: Logic and Decision Making Mitch Herschbach Spring 2011

Philosophy 12: Logic and Decision Making

Mitch HerschbachSpring 2011

UC San Diego3/29/2011

Tuesday, March 29, 2011

Instructor

• Mitch Herschbach ([email protected])

- Office: HSS 8037

- Office hours: Tues 1-3pm and by appointment


mailto:[email protected]


Teaching Assistants• Nat Jacobs ([email protected])

- Sections:

• A01: Mon 3-3:50pm Warren Lecture Hall 2207

• A03: Fri 10-10:50am Cog Sci Building 005

- Office: HSS 7054

- Office hours: Thurs 1-3pm

• Jeremy Gomer ([email protected])

- Sections:

• A02: Wed 1-1:50pm Warren Lecture Hall 2113

- Office: HSS 7059

- Office Hours: Wed 12-1pm






Course website

http://mechanism.ucsd.edu/~mitch/teaching/s11/phil12/

- syllabus

- schedule of readings

- study guides

- paper assignments

- lecture slides


http://sdcc3.ucsd.edu/~mherschb/teaching/w10/phil12

http://sdcc3.ucsd.edu/~mherschb/teaching/w10/phil12

Course materials1. Inquiry website and printed course reader

2. i-clicker Classroom Response System Transmitter (“clicker”)


1. Inquiry website

• Inquiry website: http://inquiry.ucsd.edu

• Login directions and initial login code found in printed course reader, Inquiry into Scientific Reasoning, available at Price Center bookstore

- be sure you buy a new reader--used initial logins cannot be reused

• Printed reader doesn’t include all course material--website has text, animation, interactive exercises, and questions


http://inquiry.ucsd.edu

http://inquiry.ucsd.edu

2. i>clickers

• Available at the Price Center bookstore

• You will need to bring the clickers to every lecture, starting Thursday

• For more info:

http://clickers.ucsd.edu/


Basic operation

• Turn on the clicker by pressing the bottom “On/Off” button.

- A blue “Power” light will appear at the top of the remote.

• Set frequency to AB for this course

- While clicker is off, hold power button until blue light flashes

- then press “A” then “B”

• When I ask a question in class (and start the timer), select A, B, C, D, or E as your vote.


How do you know your vote was received?

• Check your “Vote Status” Light:

- Green light = your vote was sent and received

- Red flashing light = you need to vote again.

• Not sure you saw the light? Just vote again.

• Want to change your vote? You can vote again as long as the timer is still going.


Registering your i>clicker• In order to earn points for your i>clicker

responses, you must register your i>clicker online (but don’t worry, you will still get the points from before registration).

• Go to www.iclicker.com/registration

- Fill in:

• your name

• your PID (student ID) number

• your clicker ID (located on the back of your clicker, below the scan code)

- click ENTER

Organization

Clickers

Basic operation

Registering your i>clicker

Registering your i>clicker

In order to earn points for your

i>clicker responses, you must register

your i>clicker online (but don’t worry,

you will still get the points from before

registration).

For this, you will need (your name),

your PID number (starting with an ‘A’),

and your clicker ID (located on the

back of your clicker, below the scan

code).

Christian Wüthrich Topic 0Tuesday, March 29, 2011

http://www.iclicker.com/registration

http://www.iclicker.com/registration

Other i>clicker info

• Before using a new clicker for the first time, pull the plastic tab out of the battery compartment.

• Check out www.iclicker.com for FAQs

• Email [email protected] or phone 866-209-5698 for help


http://www.iclicker.com

http://www.iclicker.com



Course requirements

1. Web-based exercises (5%)

2. Lecture participation (10%)

3. Section participation (5%)

4. Two short (1-2 page) papers (30%)

5. Midterm exam (25%)

6. Final Exam (25%)



• These points for timely completion of the interactive exercises and questions on the Inquiry website.

• Graded on timely completion, not accuracy of responses.



• Readings are titles of modules you’re expected to complete before that day’s lecture

provide a current Authorization for Accommodation (AFA) letter issued by the Office forStudents with Disabilities (OSD), prior to eligibility for requests. Receipt of AFAs in advance isnecessary for appropriate planning for the provision of reasonable accommodations. OSDAcademic Liaisons also need to receive current AFAs. For more information, contact the OSDat (858) 534.4382 (V); (858) 534-9709 (TTY); [email protected], or http://osd.ucsd.edu.

Academic IntegrityStudents are expected to do their own work, as outlined in the UCSD Policy on Integrity ofScholarship: http://www-senate.ucsd.edu/manual/Appendices/app2.htm Cheating will not betolerated, and any student who engages in forbidden conduct will be subjected to thedisciplinary process. You are responsible for familiarizing yourself with these policies;ignorance will not be an excuse. If you have any questions about these policies, feel free tocontact me.

Deadlines for AssignmentsMake-up exams (for midterm and final) or extended deadlines (for the papers) will only begiven under the most severe circumstances. Any student who wishes to take a make-upexam or needs an extension must inform me (in person or by email) before the deadline. Inorder to qualify for a make-up exam or an extension, appropriate evidence of the mostsevere circumstances must be produced by the student. I will determine, in consultation withthe student, what qualifies as appropriate evidence.

Classroom ConductPlease arrive to class on time. Students should be respectful of their fellow classmates,allowing them to finish before speaking, listening to and respecting classmates'views/opinions. In addition, students must silence all cellular telephones, pagers, and iPods,etc., before entering the classroom. Laptops and other electronic devices may not be used inclass, except for lecture note-taking.

ScheduleThis schedule is tentative and subject to revision.

The numbered reading assignments are modules on the Inquiry website; the numbering isbased on the table of contents in your printed reader. You should complete these, includingany attached questions, before the assigned class (although subsequent review is certainlyencouraged).

Date Topic Readings

Tues3/29

Introduction: The Inquiry Website andExemplary Scientific Reasoning

Syllabus

Thurs3/31 Elements of science

1. Argumentation; 1.1. Invitation to ScientificReasoning; 1.2. Statements: the atoms ofreasoning; 1.3. Justification and arguments

Tues4/5

Valid arguments 1.4. Some basic valid argument forms

Thurs4/7

Confirmation, falsification, andfallibility

1.5. Evidential relations; 1.6. The falliblecharacter of human knowledge

Tues4/12

Observation and categories 2. Observation; 2.1. Observation and learningto see

Thurs4/14

Categorizing phenomena 2.2. Categories and taxonomy

Tues4/19

Observational research 2.3 Observational research [Coding Sheet forTime-Log Project]

Thurs Distributions and samples 2.4. Variables and measurement


Interactive Exercises


Questions


Questions

Questions Some modules contain questions to help you test your knowledge of the topic of the module. There are two ways to access these questions. Option #1: The bottom of the page will contain a red "Web Project" box with a link labeled "Questions", as depicted below. Click the “Questions” link to access the questions.

Option #2: For modules containing questions, the menu on the right side of the page will also contain a "Questions" button that you can click on to access the questions, as depicted in the image below:


Questions


Checking your progress on Inquiry

19


Checking your progress on Inquiry

20


2. Lecture participation (10%)

• “Clicker score” based on in-class questions that you answer using i>clickers

• 1 point per question; graded on participation not accuracy

• Your clicker score will be the percentage of points earned divided by the maximum possible

• You must have your clicker every class period to get these points—no exceptions


3. Section participation (5%)

• Grade based on participation and performance on quizzes in section

• Sections start next week

A01 Mon 3-3:50pm Warren Lecture Hall 2207A02 Wed 1-1:50pm Warren Lecture Hall 2113A03 Fri 10-10:50am Cog Sci Building 005


4. Two short papers (30%)

• 1-2 page papers on assigned topics

• First paper due Thursday, May 12th

• Second paper due Thursday, May 26th

• Further details will be posted on course website closer to assignment dates


5-6. Midterm and Final Exams

• Midterm: Tuesday April 26th, in lecture

• Final exam: Tuesday June 7th, 11:30-2:30pm

• both are in-class exams consisting of multiple choice, short answer, and essay questions


Policy about Deadlines

• Make-up exams or extended deadlines for the papers will only be given under the most severe circumstances.

• Any student who wishes to take a make-up exam or needs an extension must inform me (in person or by email) before the deadline.

• In order to qualify for a make-up exam or an extension, appropriate evidence of the most severe circumstances must be produced by the student. I will determine, in consultation with the student, what qualifies as appropriate evidence.


Any questions about the syllabus?


Logic and Decision Making

• If we've been engaging in reasoning and decision-making our whole lives, why have a college course on it?

• We sometimes engage in bad reasoning, make bad decisions

- We're constructed in ways such that we make systematic errors in reasoning and decision making


How reliable is vision?

Are the table tops the same size or different sizes?


http://www.michaelbach.de/ot/sze_shepardTables/main.swf




How good is human reason?• Behind one of these doors I have hidden money, behind the other two

a goat

• You get to pick which one to open.

• But before you open it, I will open one of the other doors, revealing a goat

• Now I give you a choice: stay with your first pick, or change to the other.

• Which is the better option?


A Bad Doctor’s Visit

• There is a simple test he can perform which is accurate 80% of the time--that is, 20% of the time it gives false positives

• You agree to the test, and it comes back positive.

• How worried should you be? How likely are you to die?

- Answer: your risk of death is less than 4%!

• You go to see your doctor with a puzzling ailment.

• Your doctor tells you that it is characteristic of a disease that is affecting 1% of the population and if you have it, it means certain death


A Bad Doctor’s Visit• Given 1% infection rate, in a population of 1000

people:

- 10 will have the disease, 990 healthy people

• 80% of those 10 sick people will get an accurate positive test = about 8 people

• 20% of the 990 healthy people will get a false positive = about 198 people

• 8 + 198 = 206 total positive tests

• But only 8/206 (3.9%) of those have the disease


When is evidence diagnostic?

• Data from 250 patients:

Brain tumor

No Brain Tumor

Dizzy 160 40

Not Dizzy 40 10

Is dizziness associated with brain tumors? Which information is relevant?


When is evidence diagnostic?

• Data from 250 patients:

Brain tumor

No Brain Tumor

Dizzy 160 40

Not Dizzy 40 10

What % of dizzy people have brain tumors?

What % of non-dizzy people have brain tumors?

160/200 = 80%

40/50 = 80%


Sensible Policy MakingImagine that the U.S. is preparing for the outbreak of an unusual disease, which is expected to kill 600 people. Two alternative programs to combat the disease have been proposed:

- Program A: 200 people will be saved

- Program B: 1/3 chance of saving 600 people and 2/3 chance of saving no one


Sensible Policy MakingFlood waters are heading toward a town of 600 people. You are on the disaster management board and must choose one of two options:

- Program C: 400 people will die

- Program D: 1/3 chance that no one will die and 2/3 chance that 600 people will die


Sensible Policy MakingImagine that the U.S. is preparing for the outbreak of an unusual disease, which is expected to kill 600 people. Two alternative programs to combat the disease have been proposed:

- Program A: 200 people will be saved

- Program B: 1/3 chance of saving 600 people and 2/3 chance of saving no one

72%

28%

78%

22%

Flood waters are heading toward a town of 600 people. You are on the disaster management board and must choose one of two options:

- Program C: 400 people will die

- Program D: 1/3 chance that no one will die and 2/3 chance that 600 people will die


Good reasoning in science

• Science is a field where humans have developed practices to help avoid cases of bad reasoning, engage in best kind of reasoning

• We will explore what makes good/bad reasoning in science, good/bad reasoning in general

• The focus is not on the scientific examples, but on the principles of reasoning illustrated by these examples


Exemplary Reasoning in Science

Gregor Mendel’s (1822-1884)account of heredity


Understanding of heredity prior to Mendel

• It had been obvious to people for ages that offspring:

- are similar to their parents

- vary from their parents


Understanding of heredity prior to Mendel

• Animal and plant breeders capitalized on these differences

- By controlling mating and eliminating undesired organisms, breeders were able to produce plants and animals with desired traits

- By multiply breeding offspring and eliminating variants, breeders could generate pure breeds


Gregor Mendel (1822-1884)

• An Augustinian monk, Mendel studied physics and natural science in Vienna, but lived most of his adult life in an abbey in Altbrünn (now Brno in the Czech Rep)

• Starting in 1856 he conducted plant breeding experiments in the abbey’s garden


Mendel’s Breeding Experiments

• Choice of peas as organism to study: naturally self-pollinated but easy to cross-pollinate

• Mendel introduced the vocabulary of dominant and recessive “characters” (traits)


Mendel’s Procedure• Develop pure breeding lines:

populations that breed true for a particular trait

• Cross-pollinate between pure breeding lines with alternative traits (e.g., smooth vs. wrinkled seeds), creating F1 generation

• All members of the F1 generation exhibit the dominant traits

• Allow members of the F1 generation to self-pollinate, creating F2 generation

Reasoning and fallaciesExemplary reasoning in science

IntroductionMendel’s breeding experiments

Mendel’s procedure

Cross-pollinate between purebreeding lines with alternativetraits—yellow/green seeds,smooth/dented seeds etc.All members of the F1generation exhibit the dominanttraits.Allow members of the F1generation to self-pollinate.

Topic 1Tuesday, March 29, 2011

Mendel’s Experimental ResultsTypes of

TraitParental Cross F1

PhenotypeF2 Phenotypic Ratio F2 Ratio

Form of seed

Round x Wrinkled Round Round: 5474

Wrinkled: 1850 2.96:1

Color of albumen Yellow x Green Yellow Yellow: 6022

Green: 2001 3.01:1

Color of seed coat Violet x White Violet Violet: 705

White: 224 3.15:1

Form of pods

Inflated x Constricted Inflated Inflated: 882

Constricted: 299 2.95:1

Color of unripe pods Green x Yellow Green Green: 428

Yellow: 152 2.81:1

Position of flowers

Axial x Terminal Axial Axial: 651

Terminal: 207 3.14:1

Length of stem Long x Short Long Long: 787

Short: 277 2.84:1


F1 and F2 generations

• F1 generation: only displayed dominant trait

• F2 generation produced by self-fertilization of members of the F1 generation:

- Individuals with recessive traits bred pure

- 1 out of 3 of those showing the dominant character produced only offspring with the dominant character

• Theoretical problem for Mendel: what could explain these and other patterns he found?


Mendel’s Hypothesis

• Behind the characters lay “factors”

- pollen and egg cells each possessed the factor for either the dominant or recessive trait

• What evidence does Mendel have for these factors?

- Only that they account for the inheritance pattern he saw and others he predicted

- Without his hypothesis, these other predictions would not have been made

YY yy

Y y

Yy

Y y

y

Y YY

yy

Yy

Yy

P

F1

F2

YyYy

Yy

Yy


Features of Mendel’s Reasoning

• He designed a study that could reveal structure in the phenomena

• He found a systematic pattern in the phenomena

• He proposed a hypothesis that could explain the pattern

• He supported this hypothesis by both the pattern he initially observed and others which it predicted. These patterns would otherwise be mysterious!

• Message: Successfully predicting what would otherwise be mysterious is typically the way hypotheses gain support


Documents

Philosophy 12: Logic and Decision Makingmechanism.ucsd.edu/~mitch/teaching/s11/phil12/lectures/Phil12_S11... · Philosophy 12: Logic and Decision Making Mitch Herschbach Spring 2011