Turing machines, principles and practice

In principle, of course, any Turing-equivalent programming language can do the same things as any other. But that kind of power is not what programming languages are about. In principle, anything you can do with a programming language you can do with a Turing machine; in practice, programming a Turing machine is not worth the trouble.

-- Paul Graham, On Lisp pp. vii

Anthropomorphic metaphors and novelty

We could, for instance, begin with cleaning up our language by no longer calling a bug a bug but by calling it an error. It is much more honest because it squarely puts the blame where it belongs, viz. with the programmer who made the error. The animistic metaphor of the bug that maliciously sneaked in while the programmer was not looking is intellectually dishonest as it disguises that the error is the programmer's own creation. The nice thing of this simple change of vocabulary is that it has such a profound effect: while, before, a program with only one bug used to be "almost correct", afterwards a program with an error is just "wrong" (because in error).

My next linguistical suggestion is more rigorous. It is to fight the "if-this-guy-wants-to-talk-to-that-guy" syndrome: never refer to parts of programs or pieces of equipment in an anthropomorphic terminology, nor allow your students to do so. This linguistical improvement is much harder to implement than you might think, and your department might consider the introduction of fines for violations, say a quarter for undergraduates, two quarters for graduate students, and five dollars for faculty members: by the end of the first semester of the new regime, you will have collected enough money for two
scholarships.

The reason for this last suggestion is that the anthropomorphic metaphor --for whose introduction we can blame John von Neumann-- is an enormous handicap for every computing community that has adopted it.

...

Teaching to unsuspecting youngsters the effective use of formal methods is one of the joys of life because it is so extremely rewarding. Within a few months, they find their way in a new world with a justified degree of confidence that is radically novel for them; within a few months, their concept of intellectual culture has acquired a radically novel dimension. To my taste and style, that is what education is about. Universities should not be afraid of teaching radical novelties; on the contrary, it is their calling to welcome the opportunity to do so. Their willingness to do so is our main safeguard against dictatorships, be they of the proletariat, of the scientific establishment, or of the corporate elite.

-- E.W. Dijkstra, "On the cruelty of really teaching computer science (EWD 1036)." [link]

Technorati Tags: dijkstra, computer science

Language and axes

"About the use of language: it is impossible to sharpen a pencil with a blunt axe. It is equally vain to try to do it with ten blunt axes instead. "

-- E.W. Dijkstra, "How do we tell truths that might hurt? (EWD498)" [link]

Grace extended

"Do not forget, never forget, that you have promised to use this money in becoming an honest man."

Jean Valjean, who had no recollection of ever having promised anything, remained speechless. The Bishop had emphasized the words when he uttered them. He resumed with solemnity:--

"Jean Valjean, my brother, you no longer belong to evil, but to good. It is your soul that I buy from you; I withdraw it from black thoughts and the spirit of perdition, and I give it to God."

-- Victor Hugo, Les Misérables, Book I, Chapter XII, "The Bishop Works"

First post!

This will be used to collect interesting quotes and citations that I find.