From: Avdi Grimm Date: 2008-06-05T13:43:07+09:00 Subject: Re: The duck's backside On Mon, Jun 2, 2008 at 8:03 PM, David Masover wrote: > Interesting that this works -- but it doesn't disprove my point. Humans are a > category of mammals -- that doesn't imply that all mammals are humans. Humans are a category of animal with certain characteristics which set them apart form other animals. All animals which have those characteristics are human. You stated the theory that the NilClass class encompasses all objects that respond positively to #nil?. Which is easily disproved by defining a non-NilClass which responds positively to nil. MyNil is in the *category* of objects which respond to #nil? in the affirmative, but not in the *class* NilClass. Thus, NilClass != the category of objects which respond to #nil? NilClass objects may be a *subset* of the #nil? => true category, but NilClass itself does not define a category other than "objects which are instances of NilClass". -- Avdi Home: http://avdi.org Developer Blog: http://avdi.org/devblog/ Twitter: http://twitter.com/avdi Journal: http://avdi.livejournal.com