Computer Architecture (CS 146/246) – Fall 2019

Module Topic: Ethics and Energy Use in Computing
Module Author: Cat Wade

Course Level: Undergraduate
AY: 2019-2020

Course Description: “The class will review fundamental structures in modern microprocessor and computer system architecture design. Tentative topics will include computer organization, instruction set design, memory system design, pipelining, and other techniques to exploit parallelism. We will also cover system level topics such as storage subsystems and basics of multiprocessor systems. The class will focus on quantitative evaluation of design alternatives while considering design metrics such as performance and power dissipation.” (Course description)

Course instructor: David Brooks

Semesters Taught: Fall 2019, Spring 2021, Spring 2023

Tags

• climate change (phil)
• normative vs. descriptive statements (phil)
• distributive justice (phil)
• moral responsibility (phil)
• the difference principle (phil)
• hardware (CS)
• NLP (CS)
• processing power (CS)
• energy (CS)
• architecture (CS)
• geoengineering (both)

    Module Overview

This module opens with an overview of some statistics pertaining to climate change and technology use and development. With the stakes in place, we turn to clarifying the distinction between: (a) normative questions and statements; and (b) descriptive questions and statements^A. The rest of the class then draws on the students’ assigned reading which details five ethical issues pertaining to climate change. These are: skepticism about climate change, past emissions, future emissions, adaptation (adapting rather than preventing climate change), and direct intervention (geoengineering). In their homework assignment, the students are asked to read the assigned paper and restate each of the issues discussed in the form of a primary normative question^B. The student responses are then used to guide class discussions through each of these topics. In particular, students are asked to identify which arguments and counterarguments to their normative questions they find most compelling and why. These sections are, therefore, highly student driven. After first thinking in small breakout groups, the students come together as a class to discuss the arguments for and against the normative questions they have identified. During the class discussions, the Embedded EthiCS TA writes the criteria students are using to evaluate arguments on the board. Once all five topics and associated normative arguments are evaluated, the TA asks the students to consider these criteria as a whole and identify any recurring patterns^C. The TA then asks students to think of ways in which these criteria might apply to other ethical issues in CS. The module ends by picking up on one specific normative question raised in the ‘future emissions’ section and delves a little deeper: if environmental impact is a burden to be shared, how ought we to distribute this burden? To help adjudicate between some of the many options presented in the assigned reading, Rawls’ Difference Principle is presented as a possible means of choosing a path forward.

Connection to Course Material

This course looks primarily at the design, construction and efficiency of computer hardware, including processors, transformers and storage options. As such, energy consumption and economic impact are constant considerations. Considering the environmental impact of different possible design choices is thus a natural further question to ask.

Goals

Module Goals

By the end of the module, students will be able to:

1. Give students the opportunity to make and evaluate difficult ethical arguments and to criticize and provide counterarguments to their peers’ positions in a way that is constructive and grounded in sound ethical reasoning.
2. Introduce students to the distinction between normative and descriptive questions and statements.
3. Familiarize students with the idea of distributive justice and Rawls’ Difference Principle as well as giving students the opportunity to articulate how this would apply to design and policy decisions.
4. Empower students to work through papers that present a number of nuanced and often dense ethical arguments by identifying a guiding normative question and seeing how the different arguments pertain to that question

    Key Philosophical Questions

• What is a normative question or statement? What is a descriptive question or statement?
• What criteria do we use when evaluating ethical positions and arguments?
• What is distributive justice, why should it matter, and what are some possible accounts of what a just distribution is?

Materials

Key Philosophical Concepts

• Distributive justice
• Intergenerational justice
• Moral responsibility
• Positive rights (to safety, housing, etc.)
• Risk/benefit analysis
• Normative vs Descriptive questions and statements
• The Difference Principle (Rawls)

    Assigned Readings

• Gardiner, S. M. (2010). “Ethics and climate change: an introduction.” Wiley Interdisciplinary Reviews: Climate Change, 1 (1), 54-66.
• Strubell, E., Ganesh, A., & McCallum, A. (2019). “Energy and policy considerations for deep learning in NLP.” arXiv preprint arXiv:1906.02243

Implementation

Class Agenda

1. Some statistics concerning climate change and CS
2. Normative vs. Descriptive questions and statements
3. 3. Gardiner’s ‘5 areas of discussion’ in ethics and climate change
   1. Skepticism about climate change
   2. Past Emissions
   3. Future Emissions
   4. Adaptation
   5. Direct Intervention
4. Limited CS resources and just distribution
5. Concluding discussion

    Sample Class Activity

Students discuss each of Gardiner’s 5 ‘areas of discussion.’ The homework assignment (see below) serves as preparation for this discussion by asking students to identify the primary normative question at stake with each issue. In class, students are broken into small groups to discuss each issue and then reunited to share and discuss as a class. The Embedded EthiCS TA guides the discussion by breaking down the argumentative space. For example, with respect to ‘future emissions,’ after recapping the idea that cutting emissions can be thought of as a kind burden to be distributed justly, the students are presented with the following:

Who should be held responsible for cutting down future emissions?

Option 1: the bigger the past emission, the bigger the future cut

Option 2: every country should cut emissions by the same %

Options 3: the amount the country has to reduce emissions should be proportional to their socioeconomic circumstances

Discuss the 3 options: (a) Find a reason in favor and a reason against each of the options; (b) decide which option you think is the most ethical; and (c) state your position as a normative statement.

    Module Assignment

The students are assigned the two readings listed above and asked to do the following:

This module was well-received and generated enthusiastic discussion among the participating students, who were a mix of advanced undergraduates and graduate students.

• For each of these ethical issues (i.-v.) please do the following:
  1. Restate the issue raised in each section in the form of a normative question, i.e., a question about what we should do¹. For example: Should we raise taxes for the rich? Should every citizen be allowed to vote – including the incarcerated? Should we fire people if they disagree with us? Etc.
     Note that normative questions can also take the form of asking who should be held responsible for something². For example: should you be held responsible for what your kids say and do? Should someone be held responsible for what they do under the influence? (1 sentence)
  2. Using the questions you formulated in response to (a), pick one question and describe in your own words what you take to be the most persuasive answer to that question as found in the text (it can be either for or against the question you formulate) and explain why you take it to be persuasive. (3-4 sentences)
• Assume for now that the main ethical question raised in your other assigned reading is: should we reduce the amount of energy required for progress in NLP R&D? Which of Gardiner’s five ethical issues is most relevant to this question and why? (1-2 sentences)
• Finally, in the section on direct intervention, Gardiner presents the following position: “Many people, including a number of climate scientists, appear to believe that the attempt to geoengineer is not only risky, but also both an attempt to divert attention from the obligation to reduce emissions, and ultimately a sign of hubris” (63). Using considerations given in the text and/or your own views or intuitions please answer the following:
  Is the attempt to reduce the amount of energy required for progress in NLP R&D vulnerable to similar objections, namely, that it is risky, merely diverting away from some other more pressing or urgent issue, and a sign of hubris? Why/why not? (4-5 sentences)

¹ Normative questions and statements are often thought to contrast with descriptive questions or statements. E.g.: ‘it is wrong that the bank was robbed’ vs. ‘the bank has been robbed’

² Interestingly, questions of the form ‘who should have to fix this mess’ are often both normative and practical, i.e., sometimes we are not only asking: ‘who should we hold responsible for this mess’ but also ‘who is able to fix this mess?’

Lessons Learned

In our experience, students are highly participatory throughout the module. The high level of engagement is likely due to: (1) the homework assignment being designed so as to prepare them for discussion; (2) the structured breakout sessions followed by group discussion for each of the ethical issues.

Responses from the students, the CS professor, and TAs were also positive. We believe this is due to the concerted effort to constantly tie the philosophical material to the course material (in both the homework assignment and throughout the module).

Future iterations should aim to improve on time management. When students are extremely engaged and have a lot to contribute, we found that certain conversations had to be cut short and that the discussion of distributive justice at the end was rushed.