The sleep of reason produces "rationalists"

Here's an outstanding post from at Deogolwulf at The Joy of Curmudgeonry about the tendencey of some rationalists to pledge blind faith in the power of reason to cure all our ills:

For it is not rationality that prevents us from killing and enslaving one another, but rather an adherence to moral sentiments that stand thereagainst, the removal of which would leave us without protection from heartless and ruthless exploitation, as the goodly Leszek Kolakowski pointed out,

"[I]n the normal sense of ‘rationality’ there are no more rational grounds for respecting human life and human personal rights than there are, say, for forbidding the consumption of shrimp among Jews, of meat on Friday among Christians, and of wine among Muslims. They are all ‘irrational’ taboos. And a totalitarian system which treats people as exchangeable parts in the state machinery, to be used, discarded, or destroyed according to the state’s needs, is in a sense a triumph of rationality." [1]

There is indeed a kind of person who must make reason his watchword in all things, who wishes to banish all that cannot be made subject to it, lest he be thought silly or insufficiently committed to reason or even a defender of unreason. It is a strange – and indeed an “irrational” – fear, and stems from an intemperate character, being that it belongs to one of those two extremes noted by Blaise Pascal: “to exclude reason, to admit reason only”.