Both Ehrenreich and Derbyshire (for different reasons, of course) oppose the think-good-thoughts-to-create-positive-change-in-the-world school of philosophy.
For example, Ehrenreich, who has been treated for breast cancer, criticizes the notions that being positive bolsters your immune system, that you need to embrace your disease, or that cancer is a "blessing."
The flip side, she says, presumes that if you are not positive, you can produce negative outcomes and that is your fault. This is a simplified version of her views (which also consider the effects of false positivity in business and politics).
The blurb for Derbyshire's book states that if "conservatives had retained their gloom, few would have been seduced by promises of hope and change, and Barack Obama would not have won the White House."
During the second half of Book TV, Derbyshire traded barbs with Alan Colmes, formerly of Fox News' "Hannity and Colmes." Derbyshire made disparaging comments about women, liberals, and immigrants (despite having a wife who is Chinese). He came off as arrogrant, and yes, gloomy.
I agree that thinking good thoughts alone won't help you accomplish goals. That takes planning, perseverance, and action.
There have been times in my life when having a positive attitude while coping with difficult challenges helped me get through them. In some cases, it was all I had. Facing reality can be a real bummer when all doors seem closed or when one's resources are limited.
I can think of several situations when fear, insecurity, or feelings of incompetence could have immobilized me. However, I would talk myself into a more positive frame of mind. In most instances, doing so made all the difference.
So Barbara and John, I respect your views, but can't give up the belief that what we think--positive or negative--affects how we feel, and consequently, what actions we take. Our thoughts can affect outcomes.