Once a depressed person becomes active and hopeful, self-esteem always improves. Bolstering self-esteem without changing hopelessness, without changing passivity, accomplishes nothing.

It's a matter of ABC: When we encounter ADVERSITY, we react by thinking about it. Our thoughts rapidly congeal into BELIEFS. These beliefs may become so habitual we don't even realize we have them unless we stop to focus on them. And they don't just sit there idly; they have CONSEQUENCES.

The pursuit of happiness is enshrined in the Declaration of Independence as a right of all Americans, as well as on the self-improvement shelves of every American bookstore. Yet the scientific evidence makes it seem unlikely that you can change your level of happiness in any sustainable way. It suggests that we each have a fixed range for happiness just as we do for weight. And just as dieters almost always regain the weight they lose, sad people don't become lastingly happy, and happy people don't become lastingly sad.

To the scientists of the Renaissance, your critic was really your ally, helping you advance upon reality. Critics in science are not like drama critics, determining flops and successes. Criticism to scientists is just another means of finding out whether they're wrong, like running another experiment to see if it confirms or refutes a theory. Along with the advocacy principle of the courtroom, It is one of the best ways human beings have evolved to get closer to the truth.

Positive thinking is the notion that if you think good thoughts, things will work out well. Optimism is the feeling of thinking things will be well and be hopeful.

Optimism is a tool with a certain clear set of benefits: it fights depression, it promotes achievement and produces better health.

In your own life, you should take particular care with endings, for their color will forever tinge your memory of the entire relationship and your willingness to reenter it.