The Cruelty of Really Teaching Computer Science

“The Cruelty of Really Teaching Computing Science” is a 1988 paper by E. W. Dijkstra, which argues that computer programming should be understood as a branch of mathematics, and that the formal provability of a program is a major criterion for correctness.

Despite the title, most of the article is on Dijkstra’s attempt to put computer science into a wider perspective within science, teaching being addressed as a corollary at the end.Specifically, Dijkstra made a “proposal for an introductory programming course for freshmen” thatconsisted of Hoare logic as an uninterpreted formal system.

Debate over feasibility

In modern software engineering practice, formal verification is almost always considered too resource-intensive to be feasible. In complex applications, the difficulty of correctly specifying what the program should do in the first place is also a common source of error. Other methods of software testing are generally employed to eliminate bugs and many other factors are considered in the measurement of software quality.

The notion that cost of production should be a constraint in programming was foreign to Dijkstra. He viewed the cost controls as artifacts that could become excuses and the controls of nature as nonexistent in digital systems, which above the level of circuits guarantee a second, constructed nature.Fact|date=February 2007

Dijkstra, to the end of his life, maintained that computing’s central challenges hadn’t been met to his satisfaction, due to an insufficient emphasis on the program correctness (though not obviating other requirements, such as maintainability and efficiency). [See [http://www.cs.utexas.edu/users/EWD/transcriptions/EWD13xx/EWD1304.html EWD 1304 - The end of Computing Science?] ]

Pedagogical legacy

Computer science as taught today generally does not follow Dijkstra's advice. It generally emphasizes techniques for managing complexity and preparing for future changes. These include abstraction, programming by contract, and design patterns. Programming techniques to avoid bugs and conventional software testing methods are taught as basic requirements, and students are exposed to certain mathematical tools, but formal verification methods are not included in the curriculum except perhaps as an advanced topic. [See e.g. http://web.mit.edu/6.170/www/lectures/lectures.html, and courses 6.001, 6.033, 6.042, 6.170 (requirements for undergraduate CS majors) descriptions in the MIT Course Catalog at http://student.mit.edu/catalog/m6a.html]

There is also greater emphasis on the social aspects of programming, such as learning how to engineer as part of a team, and how to write code that is easily re-used by other people.Fact|date=February 2007 Some institutions focus more on practical engineering skills, such as learning popular programming languages or how to use commonly available tools, rather than the underlying theory of computer science.Fact|date=February 2007

References

External links

* [http://www.cs.utexas.edu/users/EWD/ewd10xx/EWD1036.PDF Handwritten manuscript] in PDF format.
* [http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1036.html Transcription]