In short, rationality is not the same thing as intelligence and general intelligence does not correlate with rational behavior nearly as well as we might like it to. Individuals with high intelligence can and do put their mental endowments to work to argue for mistaken ideas and execute irrational plans.
I'm now thinking of an intelligent individual who made a small misstatement in conversation, then, when challenged on that point, proceeded to explain why he was not mistaken for several minutes... then finally wised up and admitted that his original statement was wrong.
In short, rationality is not the same thing as intelligence and general intelligence does not correlate with rational behavior nearly as well as we might like it to. Individuals with high intelligence can and do put their mental endowments to work to argue for mistaken ideas and execute irrational plans.
I'm now thinking of an intelligent individual who made a small misstatement in conversation, then, when challenged on that point, proceeded to explain why he was not mistaken for several minutes... then finally wised up and admitted that his original statement was wrong.