But in logical terms alone, the notion of unintended (or
unanticipated) consequences must allow for positive as well as
negative consequences. Why should these also not be 'ironies of
social intervention'? Henshel has set out the main logical possibilities
here: reforms turn out to be better than expected, (i)
because unrecognized bad features of the previous condition are
removed; or (ii) the reform turns out to have unrecognized beneficial
features. Reforms turn out worse than expected because (i)
unnoticed or unappreciated good features of the old arrangement
are now lost; or (ii) because the reform itself turns out to have
deleterious features. 4 It is the first two possibilities which we so
often neglect.