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CRITICAL THINKING AND COMPUTER SCIENCE: IMPLICIT AND
EXPLICIT CONNECTIONS
Barry Fagin, Jim Harper, Leemon Baird, Steve Hadfield and Ricky Sward
US Air Force Academy Dept of Computer Science
2354 Fairchild Drive USAFA, CO 80840
719-333-3590
{firstname.lastname}@usafa.af.mil
ABSTRACT
Critical thinking is an essential skill for an educated society. Our experience as computer
science educators in an environment with an explicit emphasis on critical thinking has led
us to investigate the connection between the two. We describe examples of how critical
thinking skills can be developed throughout the computer science curriculum, and
suggest future avenues where the connection between critical thinking and computer
science could be fruitfully explored.
1. INTRODUCTION
Critical thinking abilities are considered a cornerstone of academic maturity and a
trademark of a well-educated person. They are particularly important at our university, a
military institution where critical thinking skills are an explicitly desired educational
outcome.
Our experience as computer scientists charged with developing critical thinking skills
in our students has led us to spend some time examining the connection between
computer science and critical thinking. This paper discusses how progress through the
discipline of computer science can develop critical thinking, and how to assist that
development through carefully chosen exercises. We believe the connection between
CS and critical thinking is stronger than the literature would suggest.
2. CRITICAL THINKING
Paul [7] describes critical thinking as an intellectual discipline for examining
information and determining validity. It is based on universal intellectual values that
transcend divisions of subject matter. Three key parts of critical thinking are clarity,
accuracy, and relevance.
Clarity is crucial to understanding the information received. Questions such as “can
you elaborate on your comment” can determine if the information is clear. Accuracy
probes the gaps between the information and factual reality. Questions like “how can we
find out if that is really true” can help determine accuracy. Relevance helps ensure that
the information received is pertinent. A skilled critical thinker can quickly distinguish
relevant facts from red herrings.
Presented at CCSC-SC 2006 Conference
Critical thinkers are also skeptical [5]. Every commander knows the poisonous effect
rumor can have on an organization. Skepticism and critical thinking are the best
antidotes to rumor, particularly in the internet age [2]. This makes the development of
critically thinking officers vitally important to the nation.
3. CRITICAL THINKING IN MILITARY EDUCATION
It is a common perception outside the armed forces that the military does not value
critical thinking1. In fact, the opposite is true.
One of us [Harper] taught critical thinking in the Air Force ROTC Program. AFROTC
course materials on critical thinking emphasize the inculcation of habits of thought and
action: The desire for clarity, accuracy, and relevance, the ability to detect logical
fallacies, and the examination of implicit assumptions.
These skills are vital to officers because of the unique nature of the profession of arms.
As part of normal day-to-day activities, members of the military may have in their
possession weapons of considerable lethality. Even officers without direct access to
weapons systems may wield considerable power and influence, particularly as computer
scientists where they may be network administrators or information warfare specialists.
The importance of a functioning chain of command in wartime, combined with the
societal need for confidence that military force will be used only when authorized under
lawful civilian control, create two opposing tendencies that officers must carefully
balance. Lawful orders must be obeyed, but unlawful orders must not. Concern with this
tension often emerges in popular culture2.
Critical thinking skills enable officers to walk the middle path, and make them more
likely to accomplish the mission. Officers who think critically are less likely to act on
rumor, are more likely to give their superiors tough messages when they need to, and are
more likely to make the right decision at the right time. They are also more likely to
spend public money correctly [2], to generate and respond to criticism effectively, and to
lead with wisdom and judgment. Officers are obligated to apply critical thinking to all
tasks in the profession of arms.
4. CRITICAL THINKING IN THE CS CURRICULUM
Critical thinking skills can be cultivated in many other ways besides programming
exercises, and at many other points in the curriculum besides the introductory courses.
We discuss a few examples here.
Figure 2 shows a simplified view of the CS major at the Air Force Academy:
1 Holsti, in [5], reported almost 80% of civilian leaders without military experience described military culture as
“rigid”. Only about 15% considered the term “creative” appropriate.
2 See for example Columbia Pictures’ “A Few Good Men” (1992) or Hollywood Pictures’ “Crimson Tide” (1995).
Presented at CCSC-SC 2006 Conference
Cryptography
Comp uter Security
and Informat ion
Warfare
Secure Networks/
Cyberdef ense
Exercise
Artificial
Intellig enc e
Computer
Graphics
Introduction to
Programming
Data Abstrac tion Computer
Organization and
Archite cture
Programming
Languages Operating
Systems
Databases and Web
Programming Networks
Algo rithms Compilers Software
Engineering I
Software
Engineering II
SENIOR
YEAR
SOPHOMORE
YEAR
JUNIOR
YEAR
Figure 1: The USAFA computer science major
Lines indicate a prerequisite relationship from the course above to the course below3;
electives are outlined in dashes. The program is CSAB/ABET accredited; most readers
at 4-year undergraduate institutions should recognize where their corresponding courses
fit in. In the sections below we offer a few examples of how we try to inculcate critical
thinking using topics drawn from the course syllabus. We hope these exercises will show
how critical thinking skills can be encouraged naturally throughout the CS curriculum,
and encourage further work in this area.
5.1 Programming languages
Students in our program use Ada for their first and principal programming language
[11]. Their exposure to other languages is normally as juniors in the programming
languages course.
For their first C program, students write a simplified Ballistic Missile Defense discrete
event simulator and then run it against scenarios using different engagement strategies.
They are then asked to analyze the results and draw conclusions. In addition to the
software development goals, our intent is to give them the opportunity to practice their
analytical and critical thinking skills within a military context.
When the course turns to object oriented languages and toolkits, we discuss both the
Java and .NET frameworks and ask probing questions regarding similarities and
differences. The goal is to lead them down certain paths to see if they are asking the
3 Software Engineering does not have formal prerequisites in the CS major because it is open to students in other
disciplines. The only formal prerequisite is senior standing.
Presented at CCSC-SC 2006 Conference
right questions to get the full perspective. Many times this discussion will lead to a
critical review of open source versus strictly proprietary capabilities.
5.2 Operating systems
A typical OS course includes lessons on process scheduling, the standard process state
machine model (e.g. blocked, waiting, running), and scheduling algorithms. This
material can be difficult to teach, because students consider it uninteresting, and tend to
miss the subtleties of how processes are handled.
Last fall, we tried a new approach using the game "foxes and hounds". Our version is
played on a wraparound grid of arbitrary size, with one student playing the fox, and the
rest playing hounds:
F
2
H
H
2
H
H
2
H
Figure 2: Foxes and Hounds
The hounds act as a team and try to catch the fox by moving into its square. The fox
tries to evade capture for as long as possible. The fox and two of the hounds can move
two spaces on each turn. We add a twist to the standard game by having the instructor
roll a die. If the result is a 1, then the player that just moved must freeze. On a 6, all
frozen players become active again.
This game maps well to the process management state diagram. Students decide the
rules for when pieces are to move. Coming up with rules for a fair game is equivalent to
coming up with a good scheduling algorithm. In the process, they discover how to think
critically about process management issues.
5.3 Artificial intelligence
Krishna Rao [5] discusses the promotion of critical thinking in an AI course through
the presentation of ill-defined problems and the use of experimental testing. We concur
that this is important, and use programming assignments that do this. But AI also
provides an excellent opportunity to promote critical thinking through the use of essay
writing. We assign four papers to read, two “pro-AI” and two “anti-AI”, and require
students to write essays on them. The papers are:
1) Computing Machinery and Intelligence, by Alan Turing [12]
2) Minds, Brains and Programs, by John Searle [10]
3) The Godelian Argument, by J.R. Lucas [6]
4) Robots, Re-evolving Mind, by Hans Moravec [8]
Typical questions from assignments include:
Presented at CCSC-SC 2006 Conference
“What are potential arguments against Turing’s thesis and how does he respond?”
“Describe the ‘Chinese room’ example.”
“Are Searle’s arguments sufficient to refute the possibility of thinking machines?”
Students approach these assignments with a common framework of questions. What is
the author's claim? Are there unstated assumptions? Are there implicit value judgments?
Where is the author not thinking clearly? Where are counterarguments not considered?
Feedback is extremely positive; students consistently rate AI as the most enjoyable
class we teach.
5.4 Software engineering
Our CS “capstone” experience is a two-semester course in software engineering. It
exposes students to a large problem they cannot solve on their own given existing time
constraints.
The intent of this exercise is to force students to question their assumptions of software
development. Class teams struggle with the organization and division of labor. They
question, for example, what a program manager does day-to-day and why they even need
one. Fortunately, since some of them may become program managers, they eventually
come around.
Students also struggle when it's time for software integration, and learn valuable
lessons about unit testing, integration testing, and delivery. They question the processes
that they have been using and learn new approaches for the development of software.
These are all lessons learned through the development and refinement of critical thinking
skills.
5.5 Other issues in upper level courses
As the curriculum becomes more advanced and programming projects become more
challenging, implicit assumptions that lead to errors in programs become both harder to
identify and more important to discover. Typically, these assumptions concern complex
components of a computer system (such as I/O devices, networks, and OS internals) to
which students have only recently been exposed. In these cases, students are likely to
implicitly adopt simplistic assumptions about component and user behavior that are not
accurate descriptions of true performance. Student critical thinking skills are further
developed during their upperclass years by requiring them to create correct software that
tests these assumptions directly.
6. CONCLUSIONS AND FUTURE WORK
Our experience as computer science faculty at a military institution, where critical
thinking is an explicitly desired outcome, has led us to carefully explore the relationship
between CS and critical thinking skills. We have learned that these skills can be
developed both implicitly, through the practice of questioning assumptions by debugging
software, and explicitly, through the creation of assignments specifically designed to test
critical thinking skills.
Presented at CCSC-SC 2006 Conference
The rich connections between CS and critical thinking are worth exploring further.
How might we assess the effect of an increased emphasis on critical thinking skills? Can
educators develop a resource for CS exercises that promote critical thinking? Do the
ideas suggested here generalize to high school CS education? The evidence suggestions
the connection between CS and critical thinking warrants further attention from the
computer science education community. We look forward to further work in this area.
7. ACKNOWLEDGEMENTS
The authors are grateful to Mike Collins of the National Security Agency for his
assistance in the preparation of this paper.
8. REFERENCES
[1] Fagin, B. Technology and the values of a liberal education. Academic Questions
(Fall 1999).
[2] Fagin, B., Baird, L. and Schweitzer, D. Skepticism and cryptography. Work in
progress.
[3] Graham, L. and Metaxas, P.T. Of course it’s true; I saw it on the internet!
Communications of the ACM, 46,5 (May 2003) 71-75.
[4] Holsti, O. Of chasms and convergences: Attitudes and beliefs of civilians and
military elites at the start of a new millennium. In Soldiers and Civilians: The Civil-
Military Gap and American National Security, Feaver and Kohn eds, MIT Press,
2001, pp 15-101 . (ISBN 0262062232)
[5] Krishna Rao, M.R.K. Infusing critical thinking skills into content of an AI course. In
Proceedings of the 5th International Conference on Technology in Computer Science
Education (ITiCSE’05) (Monte de Capaica, Portugal, June 27-29 2005), pp 173-177.
[6] Lucas, J. The Godelian Argument. Truth Journal, 14 July 2002.
[7] Moore, B., and Parker, P. Critical Thinking. McGraw-Hill, 2003. (ISBN:
0072818816).
[8] Moravec, H. Robots, re-evolving mind. Cerebrum, 3,2 (Spring 2001) pp. 34-49
(invited by Walter Donway).
[9] Paul, R. Critical Thinking: What every person needs to survive in a rapidly
changing world. Center for Critical Thinking and Moral Critique, Sonoma CA,
1990. (ISBN: 0944583040)
[10] Searle, J. Minds, brains, and programs. The Behavioral and Brain Sciences, vol. 3.,
1980, Cambridge University Press.
[11] Sward, R., Carlisle, M. et al. The Case for Ada at the USAF Academy, In
Proceedings of the 2003 ACM SIGAda Conference (SIGADA-03) (San Diego CA,
USA Dec 7-11 2003), pp 68-70.
[12] Turing, A.M., Computing machinery and intelligence. Mind, 59, pp 433-460, 1
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