core theory. In several papers, Joseph
Y. Halpern and Judea Pearl have developed the concept of causality in
artificial intelligence, but their motivations and examples suggest application to “early stage” research, just as
Bertrand Russell wrote.
I submitted this letter mainly to
prompt thinking on what role the
causality concept should play in the
progress of various areas of computer
science. Today, it is used in computer
systems, software engineering, and
artificial intelligence, among others,
probably. Should we thus aim for its
progressive elimination, leaving it a
role only in the area of explanations
and early-stage intuitions?
Luigi Logrippo, Ottawa-Gatineau,
Canada
Communications welcomes your opinion. To submit a
Letter to the Editor, please limit yourself to 500 words or
less, and send to letters@cacm.acm.org.
© 2016 ACM 0001-0782/16/07 $15.00
end, I will be sharing the article with
fellow leaders in my organization
and recommend you share it with
yours as well.
Geoffrey A. Lowney, Issaquah, WA
Professionalize CS Education Now
Computer science as a discipline has
been remarkably bad at marketing itself. With current record enrollments
in American universities, this is not a
problem, but consider how it might
play out in an uncertain future. People
today using computers, cellphones,
tablets, and automated highway toll
payment devices, as well as multiple
websites and services on a daily basis
lack a clear idea what computer scientists actually do, and that they are
indeed professionals, like lawyers, accountants, and medical doctors.
Parents concerned about the earning potential of their children and of
their children’s future spouses forever try to address the conundrum
of what academic path to take, as in,
say, medical school, law school, or
business school.
I thus propose a simple semantic
change, and the far-reaching organizational change it implies. Master’s
programs in computer science shall
henceforth graduate “computists”
and rebrand themselves as “
computing schools.” Future parents and par-ents-in-law should be able to choose
among, say, medical school, computing school, business school, and law
school. Existing Master’s curricula in
computer science would be extended
to five or six semesters, with mandatory courses in all areas of applied
computing, from the perspectives of
building systems and selecting, evaluating, adapting, and applying existing
systems in all facets of computing,
based on scientific methods and precise metrics.
When this basic framework is established, computing schools would
stop accepting the Graduate Records
Exam ( http://www.ets.org/gre) and
switch to their own dedicated entrance exam, in the same way the LSAT
is used for law school and the MCAT
for medical school. The conferred degree would be called, say, Professional
Master of Computing.
It might take a decade or more to
change the perception of the Ameri-
can public, but such change is es-
sential and should be embraced as
quickly as possible and on a national
basis. ACM is best positioned and able
to provide the leadership needed to
move this important step forward for
the overall discipline of computer sci-
ence.
James Geller, Newark, NJ
Causality in Computer Science
I would like to congratulate Carlos
Baquero and Nuno Preguiça for their
clear writing and the good examples
they included in their article “Why
Logical Clocks Are Easy” (Apr. 2016),
especially on a subject that is not easily explained. I should say the subject of the article is quite far from my
usual area of research, which is, today,
formal methods in security. Still, we
should reflect on Baquero’s and Preguiça’s extensive use of the concept
of “causality.” That concept has been
used in science since ancient Greece,
where it was developed by the atomists, then further, to a great extent, by
Aristotle, through whose writings it
reached the modern world.
The concept of causality was
criticized by David Hume in the 18th
century. Commenting on Hume, Bertrand Russell (in his 1945 book A History of Western Philosophy) said, “It appears that simple rules of the form ‘A
causes B’ are never to be admitted in
science, except as crude suggestions
in early stages.” Much of modern science is built on powerful equations
from which many causal relationships
can be derived, the implication being
the latter are only explanations or illustrations for the relationships expressed by the former.
Causal laws are not used in several
well-developed areas of computer science, notably complexity theory and
formal semantics. In them, researchers write equations or other mathematical or logical expressions. At one
point in their article, Baquero and Preguiça redefined causality in terms of
set inclusion. Leslie Lamport’s classic
1978 paper “Time Clocks, and the Ordering of Events in a Distributed System” (cited by Baquero and Preguiça)
seems to use the concept of causality
for explanations, rather than for the
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