🚀 go-pugleaf

Bertrand Russell came up with a paradox, about some sets being members of 
themselves (and some not).  It is fully stated in any Dictionary of 
Philosophy.
  If you have a set of horses, then the set of non-horses includes itself, 
as such.
  But this put sets on a par with real objects, such as horses, whereas sets 
exist only in the mind of man - they have no actual existence, apart from 
that.
  Sets are collectives, and any set needs a set-er.
  An Irish setter was sitting in a corner, gnawing a bone; when it stood up, 
it fell over.
  Which shows self-referencing should be avoided, with a bone being outside 
the setter.
   Science deals with real objects, their enumeration and classification.
   Philosophy deals with mental "realities", words, and numbers, 
irrespective.
   Religion deals with human desires, eg, Eternal Life, and argues backwards 
from such conclusion.