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Midterm Review 25 February 2008 What does a Computer Do Well? Intelligence amplifier Does repetitive tasks quickly and correctly amplifies our ability to perform mental activities “power tools” for the mind Can process much more information Check things more quickly Removes people from boring tasks Manipulates forms and data What a Computer Does Very simple machine: executes exactly what it is told Executes instructions that define algorithms Instructions stored in the computer are the software We can change them Instructions deal with holders of data, not the data itself Gives them the ability to deal with any data Makes computers the most adaptable tool Logical organization of computer system CPU Inputs programs data Outputs Memory information Programs & Data/info in use now Storage LOTS of programs and data files stored here What is stored in the Computer? Bits: ones and zeroes Why? Easy to build To make managing information easier, stored in fixed size packets: Bytes (8 bits), Half words, Words, ... Storing Numbers: Binary Positional System 8 4 2 1 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 1 0 1 0 = 0 = 1 = 2 = 3 = 4 1= 0 Data Types Computer doesn’t know what the bits represents or what format is being used Computer assumes that the instructions know the format of the data Data Types Numbers: integers and floating point numbers (scientific notation) Text: Unicode, double byte Languages and symbols (Word insert symbol) Pictures: pixels Why do we need floating point numbers? A very fine needlepoint How to represent color? Sound: different formats Instructions The Internet What is it? The infrastructure that connects identified computers Links = the wires Routers = the boxes that connect them World Wide Web Computers that contain information to be shared Servers How Networking Works Need to know where to go and how to et there Who identified by IP address Every machine that is connected to the network has one Routers know how to get there But IP addresses aren’t user friendly Give names instead Domain Name Server does the mapping Benefits and Risks Most benefits are obvious Productivity tools Medicine Education Assistive technologies … But with benefits come risks… Risks Software failures Networking breaches Technology often evolves faster than our ability to handle Try to do everything with technology Software Problems Usability Bad Design Reliability Programming Mistakes Why is it so hard? Why can’t we get it right? Is this a Problem? “Our civilization runs on software, yet the art of creating it continues to be a dark mystery, even to the experts. And the greater our ambitions, the more spectacular we seem to fail.” Scott Rosenberg, “Dreaming in Code” Characteristics of a Useful Tool Help you achieve WHAT you want, in less time, with minimal effort…. Do ALL that you need … Easy to learn (intuitive) Easy to remember Standardized Why are bugs hard to find? The error can appear in another program Device drivers, memory management The error may only occur occasionally May require multiple conditions to occur User Interface Bug Afghanistan War (December 2001) Friendly fire kills 3 injures 20 when satellite-guided bomb landed on a battalion command post Use of GPS Receiver to determine coordinators Change battery Own location came up, not the one that had been entered Lots of Examples of Software Bugs Therac 25 FBI Virtual Case File Rocket launches, ... Networking Problems Data can be read Data can be lost Data can be changed Data can be sent to someone else People assume they know who owns the site Easy-to-discuss RISKS • Technostress • Multitasking • Sidetracking Kling Analogy First viewed as a clean technology Easy to See the Benefits Easy to identify Want to see them Is it possible to identify every side effect or impact? What about unintentional side effects? Ethical responsibility to try to look at consequences Role of Ethics Framework to evaluate and reason Philosophical study of morality Ethical issues must be voluntary and related to morality Fundamental purpose of morality: to advance the common good Core values Ethical Theories Ethical relativism Individual (or subjective) Cultural Normative ethical theories Deontological Kantianism Contractualism Teleological Utilitarianism Just consequentialism Normative Ethical Theories Deontological: based on the sense of duty Right because of the act Teleological: based on the result Right because of the result Deontological Theory What is it? Based on our duties and responsibilities Actions are fundamentally right or wrong Examples 1724-1804 Kantianism (Kant) Contractualism (Hobbes, Rousseau) 1588-1679 1712-1788 Kantianism: Ethics of Duty Duty as freely imposing obligation on one’s own self Duty is internal We impose duty on ourselves Kant’s Categorical Imperatives Universality: “Always act in such a way that the maxim of your action can be willed as a universal law of humanity.” Respect: “Always treat humanity, whether in yourself or in other people, as an end in itself and never as a mere means.” Strengths of Kantianism Rational Produces universal moral guidelines Treats all people as moral equals Strengths and Criticisms Strengths Rational Produces universal moral guidelines Treats all people as moral equals Criticisms Moral minimalism: requirements are not heartfelt Moral alienation: alienated from feelings No way to resolve conflict between rules Allows no exceptions Contractualism Social Contract Theory: duty not to interfere with others’ rights Morality consists in the set of rules, governing how people are to treat one another, that rational people will agree to accept, for their mutual benefit, on the condition that others follow those rules as well. James Rachel, The Elements of Moral Philosophy Rawls’s Principles of Justice Each person may claim basic rights and 1921-2002 liberties as long as these claims are consistent with everyone else having a claim to the same rights Social and economic inequalities must Be associated with positions in society to which everyone has an equal opportunity Be of the greatest benefit to the least-advantaged Strengths and Criticisms Strengths Framed in terms of rights Explains acting out of self-interest when there is no common agreement Provides framework for moral issues dealing with government Criticisms Doesn’t address actions that can be characterized multiple ways Doesn’t address conflicting rights Term Projects A thesis needs to be a statement that you are willing to defend It should not be a black or white statement Rework for Monday Teleological Theory What is it? Something is good based on its consequences Primary example: Utilitarianism Jeremy Bentham John Stuart Mill 1748-1832 1806-1873 Utilitarianism Greatest Happiness Principle Compute the costs and benefits Simple calculation: do positives outweigh the negatives? Two forms Act – judge the consequence of a specific act Rule – judge the consequence of the generalized rule Strengths and Criticisms Strengths Focus on happiness Down to earth Appeals to many people Comprehensive Criticisms Ignores our sense of duty Range of effects that one must consider Requires that we balance very different aspects Unjust distribution of good results Just Consequentialism James Moor (Dartmouth) Consider consequences of action… but combine w/deontological ideals Consider duties, rights, and justice Protect against unnecessary harm (suffering), where harm = loss of core values life, happiness, abilities, security, knowledge, freedom, opportunities, resources Applying Just Consequentialism A decision or action is ethical if It does not cause any unnecessary harm to individuals and groups Supports individual rights Fulfills duties Beyond Ethics Regulators in Physical Space (Lessig) Law (sanctions) Social norms (behavior) Market (cost) Architecture (self-enforcement)