Aristotle and the art of software development

Jonathan Dahl

http://tumblon.com (work)http://zencoder.tv (product)http://railspikes.com (blog)

Or: what does Athens have to do with Silicon Valley?

Jonathan Dahl

http://tumblon.com (work)http://zencoder.tv (product)http://railspikes.com (blog)

Athens Silicon Valley

Ethics.

G

PG

PG-13

R

Ethics.

What makes a good programmer?

What makes a good programmer?

What makes a good programmer?

Act - Effect

Anatomy of an action

Actor

Deontology (Kant)

Act - Effect

Actor

Utilitarianism (Mill)

Act - Effect

Actor

Virtue (Aristotle)

Act - Effect

Actor

Immanuel Kant

Königsberg

deontologyduty

Principles

Act only according to that maxim by which you can at the same time will that

it should become a universal law

Categorical Imperative

Don’t Repeat Yourself100% Test CoverageWrite readable code

1.User stories are written.2.Release planning creates the schedule.3.Make frequent small releases.4.The Project Velocity is measured.5.The project is divided into iterations.6.Iteration planning starts each iteration.7.Move people around.8.A stand-up meeting starts each day.9.Fix XP when it breaks.10.Simplicity.11.Choose a system metaphor.12.Use CRC cards for design sessions.13.Create spike solutions to reduce risk.14.No functionality is added early.15.Refactor whenever and wherever possible.

16.The customer is always available.17.Code must be written to agreed standards.18.Code the unit test first.19.All production code is pair programmed.20.Only one pair integrates code at a time.21.Integrate often.22.Use collective code ownership.23.Leave optimization till last.24.No overtime.25.All code must have unit tests.26.All code must pass all unit tests before it can be released.27.When a bug is found tests are created.28.Acceptance tests are run often and the score is published.

XP Rules

Don’t Repeat Yourself

Write clear, understandable code

development: adapter: mysql encoding: utf8 database: app_development username: root password:

test: adapter: mysql encoding: utf8 database: app_test username: root password:

production: adapter: mysql encoding: utf8 database: app_production username: user password: password

standard: adapter: mysql encoding: utf8 local: username: root password: development: <<: *standard <<: *local database: app_development

test: <<: *standard <<: *local database: app_test

production: <<: *standard database: app_production username: user password: password

<% local_password = "" -%><% local_user = "root" -%><% [{:name => "development", :user => local_user, :password => local_password}, {:name => "test", :user => local_user, :password => local_password}, {:name => "production", :user => "user", :password => "password"} ].each do |environment| -%><%= environment[:name] %> adapter: mysql encoding: utf8 database: app_<%= environment[:name] %> username: <%= environment[:user] %> password: <%= environment[:password] %><% end -%>

John Stuart Mill

John Stuart Mill

Opposed slaveryFavored women’s suffrageFree markets(...with proper regulation)Animal rights Environmentalism

...way before these things were cool

Opposed slaveryFavored women’s suffrageFree markets(...with proper regulation)Animal rights Environmentalism

John Stuart Mill

Utilitarianism

Greatest good for the greatest number

The ends justify the means

Lisp vs. Perl

Act - Effect

Actor

Philosophy

PhilosophyEthics

PhilosophyEthicsPolitics

PhilosophyEthicsPoliticsRhetoric

PhilosophyEthicsPoliticsRhetoric

Aesthetics

PhilosophyEthicsPoliticsRhetoric

AestheticsPsychology

PhilosophyEthicsPoliticsRhetoric

AestheticsPsychology

Biology

PhilosophyEthicsPoliticsRhetoric

AestheticsPsychology

BiologyPhysics

PhilosophyEthicsPoliticsRhetoric

AestheticsPsychology

BiologyPhysics

Astronomy

PhilosophyEthicsPoliticsRhetoric

AestheticsPsychology

BiologyPhysics

AstronomyEconomics

PhilosophyEthicsPoliticsRhetoric

AestheticsPsychology

BiologyPhysics

AstronomyEconomics

Logic

:ethics

:ethics == : “a life well lived”

:ethics == : “a life well lived” == :happiness

:ethics == : “a life well lived” == :happiness

Eudemonia (happiness)eu: gooddaimon: spirit

:ethics == : “a life well lived” == :happiness == :virtue

:ethics == : “a life well lived” == :happiness == :virtue

CourageTemperance

PrideGenerosity

Good temperTruthfulness

WitFriendliness

ModestyRighteous Indignation

Excess (too much) Virtue (just right) Defect (too little)Rashness Courage Cowardice

Temperance

Pride

Generosity

Good temper

Truthfulness

Wit

Friendliness

ModestyRighteous Indignation

Excess (too much) Virtue (just right) Defect (too little)Rashness Courage Cowardice

Indulgence Temperance InsensibilityVanity Pride Lack of ambition

Prodigality Generosity IlliberalityIrascability Good temper Lack of spirit

Boastfulness Truthfulness False ModestyBuffoonery Wit Boorishness

Obsequiousness Friendliness CantankerousnessShyness Modesty Shamelessness

EnvyRighteous Indignation

Spitefulness

practical wisdom

bootstrapping

modeling

Habits vs. RulesJudgment vs. Ends

Habits vs. RulesJudgment vs. Ends

Empower programmers

Self-effacing

Pleasant to write

Happy and virtuous

virtues, not rules

virtues, not rulesmoderation, not excess

virtues, not rulesmoderation, not excessjudgment, not process

virtues, not rulesmoderation, not excessjudgment, not processwhole of life

virtues, not rulesmoderation, not excessjudgment, not processwhole of lifehappiness

Thanks!

Slides at:http://railspikes.com

Aristotle, Nicomachean Ethics