Monday, March 1, 2010


Pascal Costanza wrote:
Student A's statement is self-contradictory. You can only meaningfully talk about making something incorrect when you have a correct meaning in mind in the first place. So for Student A, the program has a meaning, even if he/she denies that.
Student A might argue: “The professor is the one that is assuming there is a correct meaning. I'm simply pointing out that whatever meaning he might have in mind could be wrong.”

Student C's description of the program is circular. He/she states that FACTORIAL implements factorial, which doesn't say much at all - it's both times the same word, both times the same string of characters (only once in upper case and once in lower case).
Student C replies: “Oh, I meant that the program named FACTORIAL implements the mathematical function ‘factorial’.” (This is a beginner's course, so we shouldn't make him work too hard.)

Alexey wrote:
I would say to student A: That answer is useless. Of course someone could shadow * or IF; but what did the author of the program mean when they wrote it?
Student A replies: “How should I know? I can't read minds!”

What do we say to Student A?

I would say to student B: OK, that's what the program does, for a few trials with a few arguments, but what it does is beside the point. The question was: what does the program mean?
Student B asks: So what is the difference between what it “means” and what it “does”? Doesn't “(+ 2 3)” mean 5? Doesn't “(factorial 4)” mean 24?