Question about None

John O'Hagan research at
Sun Jun 14 05:17:45 CEST 2009

On Sat, 13 Jun 2009, John Yeung wrote:
> On Jun 13, 5:22 pm, "Rhodri James" <rho... at>
> wrote:
> > Such an understanding would be clearly wrong in the context
> > in which we were talking (and denotational semantics is a
> > branch of category theory, which is not specific to computer
> > science if you don't mind).  If None is nothing, then it can't
> > be a string, int, float or anything else, because they're all
> > something.
> I appreciate your explanation, and your politeness.
> And I accept your answer, as well as Steven's and Paul's for that
> matter.  I still think it is understandable (and people may choose to
> understand in a condescending way, if they wish) that someone might
> not get the difference between what you are saying and the statement
> that all elements of the empty set are floats.  I mean, what's in the
> empty set?  Nothing.  But you've said that floats are something.  How
> is it that nothing is something?

Also accepting that Python's implementation of None and all() are well-defined 
and practical, I would add that philosophically these matters of emptiness and 
nothingness are far from concluded. Bertrand Russell, for one, would have 
disputed the behaviour of all([]), although he may have appreciated its 



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