[Chicago] PyPy

[Joshua Herman]

Let us call a set "abnormal" if it is a member of itself, and "normal"
otherwise. For example, take the set of all members of ChiPy. That set
is not itself a member of ChiPy, and therefore is not a member of the
set of all members of ChiPy. So it is "normal". On the other hand, if
we take the complementary set that contains all non-members of ChiPy,
that set is itself not a member of ChiPy and so should be one of its
own members. It is "abnormal".

Now we consider the set of all normal sets, R. Attempting to determine
whether R is normal or abnormal is impossible: If R were a normal set,
it would be contained in the set of normal sets (itself), and
therefore be abnormal; and if it were abnormal, it would not be
contained in the set of normal sets (itself), and therefore be normal.
This leads to the conclusion that R is neither normal nor abnormal:
Russell's paradox.