Full Idea
There is a certain moral woodenness or even insolence in Kant's blank regard for consistency. It smacks of Keynes's Principle of Unfairness - that if you can't do a good turn to everybody, you shouldn't do it to anybody.
Gist of Idea
Kant's love of consistency is too rigid, and it even overrides normal fairness
Source
Bernard Williams (Morality and the emotions [1965], p.226)
A Reaction
He says it also turns each of us into a Supreme Legislator, which deifies man. It is clearly not the case that morality consists entirely of rules and principles, but Williams recognises their role, in truth-telling for example.
Book Reference
Williams,Bernard: 'Problems of the Self: Papers 1956-1972' [CUP 1979], p.226