Placebos work about one third of the time. This is a fact. Study after study confirms this. In trials of new drugs, the performance of the tested drug is compared with a placebo, and the drug is only considered to have a real beneficial effect if it out-performs a placebo, and often the drug, which actually has some genuine chemical effect on the patient, fails to out-perform the placebo.
This explains why all sort of “complimentary” medical treatments, such as holding crystals, chanting, smelling various smells and other daftness, work. The people who go in for such treatments are of course amongst the most gullible on Earth, and so respond particularly well to placebos. One could scoff at them, and say that they should stay away from “holistic” charlatans. Then again, since the treatments have an effect, be it a placebo effect or not, one could also argue that the patients are receiving a genuine benefit from the treatment.
We feel that we are affected by outside influences when we notice changes in our bodies. In fact, it now seems, internal mechanisms cause the changes we notice, and these are responding to changes which we don’t notice.
If you hypnotise someone, and tell them that an unlit candle in front of them is in fact lit, then when you tell them to hold their finger in the “flame”, they will, remarkably enough, develop a blister. They have not sustained any burning damage. The blister which appears after a real burn, one can conclude, is not caused by the burning damage, but is instead the body’s response to perceived burning.
People used to think that flu caused a rise in temperature. The hot fever experienced by the flu sufferer was something which the virus caused, and was a sign that the body was not working properly. Modern research has shown that this is not the case. In fact, the rise in temperature is something which the body does to itself. It does this in order to create an environment unconducive to the virus replicating inside it. Similarly, coughs, sneezes, tiredness, sleepiness, and all manner of similar symptoms usually turn out to be the body’s defence against invaders rather than some malicious and deliberate effect on the part of the invader. The invader has evolved to live happily in the body of the host, and so it generally wants that host to carry on as normal. An ill person who feels terrible and spends a week in bed, is a person whose instincts have made him dedicate a week to the fighting of an infection. Remember, evolution is not a force which is there to make people happy, it is a force which happens to act in the favour of people’s survival and reproduction. The symptoms of flu are cruelties designed to be kind.
So far, I have not written anything which you’ll be unable to find in a hundred publications. I’m now going to suggest that this explains why placebos work. Your body has to perceive a situation in order to react to it. The reaction is subconscious. The triggering of the reaction is through the brain. The hypnotised person’s brain, at some subconscious level connected with the perception of the falsely lit candle, sends a signal to the body to create a blister. It would not do this if it thought that everything were okay. Give a gullible person a placebo which they believe will cure their malady, and they then believe that everything is all right, and so they subconsciously switch off their various body reactions to the problem.
So does this make placebos good or bad? It could be that a person has nasties breeding within him, and that his body starts a sensible scorched-earth policy, raising his temperature to a degree hostile to his invaders, trapping them in mucus and sneezing them out, and enforcing rest. This man might then take a placebo, switch off all his symptoms, but still have the invader breeding, unhindered, within him.
Experiments have been done with Paracetamol, which is a drug which lowers feverish temperatures and calms headaches. People with mild non-life-threatening maladies are found to stay ill for longer if they take the drug. But they still recover. These are healthy well-fed people who do not need to fend for themselves in a harsh environment. Presumably, in the environment of our ancestors, people with the same mild illnesses would have been better off suffering the symptoms, but they would have been less comfortable. In a modern environment, in which people have to get on with their careers, the risk of serious damage or death is so low, that we can probably afford to take the drug, and forgo the unpleasant symptoms.
On the other hand, if one were to have a genuinely nasty illness against which the body should do all it can, a placebo could be very dangerous. It might switch off or lessen the body’s effective responses to attack, and at the same time offer no actual chemical benefit. Effective drugs which have an innate effect of their own can help to fight disease, but placebos by definition do nothing themselves to help. They, I suggest, fool the body into thinking wrongly that everything is fine.
If your kids are playing a bit roughly with each other in the park, you could intervene and shout at them and scold them and give them no supper, or you could just say never mind and let them get on with things. They are unlikely to come to great harm. When invaders from Mars turn up and start firing a deadly heat ray about the place, you could just say, “Never mind. They’ll probably catch a cold and die,” but then again, it might be a better course of action to abandon your house and belongings, and run away, terribly fast. One has to make a judgement about the seriousness of the situation. Similarly, if you have a very serious illness, run to a doctor, not an aromatherapist.
The above reasoning can also be used to explain why gullible people are such lucrative sources of business for "holistic/alternative/complementary medicine". If a gullible person goes to a charlatan medical practitioner, then that practitioner can make the person feel ill using the same mechanism that causes placebos to work. If a person becomes convinced that he is allergic to rice pudding, then his subconscious will trigger in his body the symptoms of illness the next time he is thrown into a bath of rice pudding. Since there is nothing wrong with him really, a placebo will put him right, and the charlatan can sell the patient an effective treatment - "Just wear these magic ear-muffs and hum the theme from Battlestar Galactica..." Only in very gullible people is this dangerous. For normal people, the concern of friends who remark that one is looking a bit off-colour might be useful, and might make one take it a little bit easier for a while, which might avoid unnecessary suffering in the long run. This explains how people might have evolved an ability to feel ill when they are fine.