Should certain abstract classes be instantiable?

[Ary Borenszweig]

Andrei Alexandrescu wrote:
> Jarrett Billingsley wrote:
>> On Thu, Oct 1, 2009 at 11:48 PM, Andrei Alexandrescu
>> <SeeWebsiteForEmail at erdani.org> wrote:
>>>> But.. you mark something abstract when you want it to be .. abstract.
>>>> How would you argue that abstract is basically a no-op when used on
>>>> methods with bodies?
>>> It's not a no-op. Try it.
>>
>> Yeah, not *currently*, but isn't that what you're proposing?
> 
> No. I think it would help going back to my original message instead of 
> asking one-liner questions. This would work much better in real life, 
> but it's a time sink in a newsgroup. You spend five seconds on asking a 
> question with a foregone answer just because you don't want to invest 
> fifteen seconds in re-reading my initial post, and then you have me 
> spend five minutes explain things again. It's counter-productive.
> 
> If a class defines an abstract method and also provides a body for it, 
> it still requires the derived class to override the method. So abstract 
> still has some meaning.

Umm... so it defines a body that will never be used because that class 
can't be instantiated and the method must be redefined by subclasses? 
Isn't that the same as "doesn't provide a body"?