Unlike the three reprobates awaiting crucifixion in the Life of Brian who urge us to ‘Always Look on the Bright Side of Life’, Barbara Ehrenreich in her latest book, Smile or Die: How Positive Thinking Fooled America and the World, eschews the smile-in-the-face-of-death outlook that has beguiled so many of its advocates from breast cancer sufferers and company employers to life coaches and motivational gurus for the poor and destitute. She sees positive thinking as a dangerous delusion masquerading as a cure for all our ills.

I went to hear the atheist Ms Ehrenreich give a ‘sermon’ on her new book at Conway Hall – that popular church of atheists and humanists who spurn the fairy-tale fantasies of conventional religious believers. On an icy-cold Sunday morning, 500 people crammed into the main assembly rooms to hear her words of wisdom.

Ehrenreich’s first experience of the horrors of positive thinking occurred eight years ago when she was tested positive for breast cancer. She was desperate for supportive sisterhood; instead she was offered pink ribbons, a pink breast cancer teddy bear and a gift bag of pink teeny-bopper paraphernalia that included a box of crayons. ‘Crayons?!!!’ she asked incredulously, ‘what are they for?’ ‘So you can express your feelings’ she was told. As an established writer and author of fourteen books, including the bestselling Nickel and Dimed and Bait and Switch she was incensed. This infantilisation of adults in the face of what was for her a frighteningly traumatic experience made her want to throw up.

She was angry about her diagnosis and wanted to find out about cures but when she questioned the lack of available treatment on the Komen Foundation site – a major breast cancer website – she was admonished for her negative attitude to her disease and ordered to run to a therapist for counselling.

Positive thinking, we are told, boosts the immune system and so fights the cancer. There is no evidence for this. In fact, Ehrenreich argues, the opposite is more likely. As a graduate in cell immunology, she knows her macrophages from her viruses and informs us that the immune system fights foreign invaders not cancer cells which are part of the bodies own system. Macrophages are often found clustered around cancer cells but they do not recognize them as alien and sometimes help to make them grow faster. In any case, if the immune system was so important why would the medical profession advocate chemotherapy which depletes the immune system?

One sickening aspect of positive thinking in relation to breast cancer is the way some sufferers perceive their disease as a ‘gift’ because it has made them re-evaluate their lives and seek fulfilment and reward in the life they still have. Celebrity victims, like the late Jade Goody or Kylie Minogue wore their baldness with pride and a sign of their special status and were almost sanctified by their followers.

Having discovered the harmful effects of positive thinking in the breast cancer world she began to see its invidious growth in many other areas of our lives that began to spawn a whole new industry: personal life coaches, motivational speakers, self-help books, successories (as opposed to accessories) – epitomised in the life is good product range and DVDs about hitherto undiscovered secrets that could enhance ones life.

James Arthur Ray was one such life coach who professed the benefits of sweat lodges in New Mexico. Three people died in one when their complaining about the heat was waived off as negative thinking. Mr Ray was not prosecuted.

In the workplace, positive thinking is not voluntary. It is imposed. Staff are forced to endure motivational speakers at all day conferences. The popular book in the corporate world, Who Moved My Cheese: An Amazing Way to Deal with Change in Your Work and in Your Life by Spencer Johnson, is really about saying that if you’re gonna be downsized, you’d better get used to it.

Ehrenreich believes it was in the 1980s when the brutal fact of downsizing was being felt that the trend of positive thinking took off. It was seen as a way for employers to help their downsized staff cope with the consequences of unemployment. Look on it as an opportunity or a transition. In fact it was a way of squeezing more out of everyone. Job seekers were told that being hired depended on their attitude. A positive attitude thus became the new cure for unemployment. By the 1990s this trend had hardened towards eliminating negative people in the workforce – those who were asking too many questions or expressing doubts about the efficacy of a new business plan.

In the arena of personal aspiration, positive thinking has regressed to a medieval mysticism shrouded by pseudo-scientific claims misappropriated from the field of quantum physics. Visualise what you want and it will come to you – a coveted necklace or a really good parking place. This is the message of The Secret, a book and DVD I was persuaded to watch by my sister in South Africa a couple of years ago. Harness your powers and you can have anything you want. If you put out positive vibes, it will return tenfold. Conversely, negative energy attracts negativity.

Another book, Secrets of the Millionaire Mind says one should place hand on heart and say ‘I love rich people’. My sister belongs to a group called the ‘Millionaire’s club’ who meet once a month to practice this philosophy and share positive energy stories.

Ehrenreich rightly sees the cruelty inherent in this new fad of positive thinking: the implication that poor people are poor because they are inwardly resisting wealth. Cancer victims are deteriorating because they have a negative attitude to their body. Oncology nurses told Ehrenreich that they feel the whole positive thinking imposition as an added burden on their patients.

It’s not surprising that the shrill exhortations of the positive attitude brigade coincide with a global pessimism about human action and its impact on climate change. They are both sides of the same fatalistic coin. You can’t change or improve the circumstances in which you find yourself so you need to change your attitude or your behaviour.

‘Positive thinking is a dangerous delusion’ says Ehrenreich, ‘but the alternative is not negative thinking – it is realism; figuring out what is going on and doing something about it. It is about creating movements to fight for social change. Above all it is about determination.’ She cites the American Declaration of Independence as illustration. ‘Those that wrote and signed the document had no certainty about winning the war of independence. Even to sign the document was held to be high treason; but they took the risk and fought. They gave it their best shot and they succeeded.’

I agree with Ehrenreich. We should shut the door of reality on the positive thinking brigade and get on with the job of changing the world by fighting against inequality, poverty and disease and fighting for the freedom we need to get the job done.