It needed also a sort of athleticism of mind, an ability at one moment to make the most delicate use of logic and at the next to be unconscious of the crudest logical errors.

• 这也需要一种脑力体操的本领，能够一方面对逻辑进行最微妙的运用，接着又马上忘掉最明显的逻辑错误。