Before Kahneman and Tversky exposed our thinking biases, there was R. W. Jepson in the 1940s who set ground rules towards clear thinking. I always believed that consistency was important, and still do.
I realized, however, that it is only important with respect to values and ethics. Integrity and responsibility are manifestations of consistency and dedication towards doing the moral thing. However, because men are fallible, inconsistency is actually a positive trait when it comes to knowledge. What I mean is that if we adjust our perspectives to novel and illuminating data, it makes us more mature individuals precisely because we are not tied to our own prejudices.
For example, when I was younger, I thought that atheists were evil. As I grew older, however, I realized that many people who did not believe in God were better people than many of those who did, so I adjusted my perspective: I now believe that there are many good atheists, and also believe there are many bad Catholics.
Our malleability to new information is a form of inconsistency, but it is one of the strongest proofs of our maturity. This book is good precisely because it saw this truth.
The conclusion is highly similar to Kahneman's introduction in Thinking, Fast and Slow: "In forming our opinions, we can fight against the temptation to take the line of least resistance... Clear thinking will not help us to form our ideals; it will help us to show how far they are feasible, how they can be attained, how far they are compatible with one another; it can inform our ideals, it may transform them, but it cannot create them."