Isn't bool __invert__ behaviour "strange"?

[Lawrence D'Oliveiro]

In message <1158959361.458232.278660 at h48g2000cwc.googlegroups.com>,
MonkeeSage wrote:

> I don't really see anything wrong with creating a custom class for
> evaluating those kinds of logical statements. It does make the code for
> statements more concise and easy to follow (with less binding
> ambiguity).

Why not express everything in Conjunctive Normal Form?