The Three Basic Mental Activities

"Thinking, willing, and judging are the three basic mental activities; they cannot be derived from each other and though they have certain common characteristics they cannot be reduced to a common denominator." This is how Arendt starts the "Mental Activities in a World of Appearances" section on page 69. Would the common denominator not be thinking? Do we not think when we judge? Do we not think when we are willing? Do we not think when we are thinking? Though we do some things out of habit and it doesn't require much mental capacity, almost everything everything requires at least some thinking. When we are judging someone, especially for their behavior, we are thinking "Why would he do.... It's so immoral!" or "I can't believe she.... She's going to hell." We are trained to know the difference between right and wrong, and when we or someone else does something wrong, we instinctively know it's not right. Is knowing not thinking?