How homeopathy works in animals and people

Why Homeopathy 'Works'

If you want to know why homeopathy works, ask an aircraft pilot.

When flying in a cloud, with no horizon you can see, there’s an almost overpowering urge to trust your senses (your vestibular system and the weight on your backside), which are ‘telling you’ that the aircraft is flying straight and level, when in reality it’s in a shallow dive into the ground. The flying instructor’s mantra is: “Ignore your senses and trust the aircraft instruments, or you will crash and you will kill yourself.”

Personal observation and patient anecdote are the medical profession’s equivalent of the pilot's vestibular system. Profoundly flawed.

Randomised, controlled trials are akin to the aircraft instruments. Not infallible, but if they’re well built, rarely wrong.

In this analogy, we find the answer to why homeopathy ‘works’ for millions of people around the world. It’s not because homeopathic remedies have any effect on human or animal illness or disease.

They don’t.

It’s because patients and some medical professionals believe they have seen an effect. That urge to believe what you see in front of you is every bit as compelling as the urge a pilot feels to keep flying ahead even as the aircraft spirals into the ground. Perhaps more so, because of all the senses, it’s the eyes that we place greatest faith in.

So, what are the human errors of interpretation that trick both trained professionals and the public into thinking homeopathy has worked for them or their patient?

Regression to the mean

Perhaps the most common is ‘regression to the mean’. In short, we usually give (or take) medication when we’re feeling unusually ill. So we’re statistically likely to start feeling better (return to the mean) regardless of whether we take a medicine or not. But if we do, the urge to believe the improvement was due to the medication is very difficult to shake.

False cause fallacy

Closely related is the false cause fallacy, whereby we draw false conclusions based on the order of events. In other words, I gave (or took) the pill on Thursday and the symptoms improved on Friday, therefore the pill eased the symptoms. Not necessarily.

Assessment errors

Equally common, but more insidious, are assessment errors. Patients and professionals alike rely on subjective assessments of the symptoms of many diseases in order to judge whether they’ve seen an improvement as a result of treatment. Of course, everyone knows when a broken leg has knitted. But the more subjective the symptoms - a cough, a rash, lethargy - the greater the potential for error.

Confirmation bias

Confirmation bias is another major human flaw. It is proven that we all have a tendency to interpret information in a way that supports our beliefs and preconceptions. We’re told we’re being given a miracle cure. We trust the person telling us, so we believe it. Thereafter, we tend to select information that supports that belief and reject any that contradicts.

Placebo effect

Finally, there’s the placebo effect, where some patients experience an actual benefit of treatment triggered not by the remedy itself, but by their belief in it. Various studies have suggested that the more subjective the reported symptoms, the greater the effect. In other words, you’re more likely to experience a reduction in pain or nausea than you are to see a reduction in blood pressure.

So, to summarise, if you were to give a sample group of people a medication made from brick dust (whether or not you dilute it) and tell them it’s a miracle cure:

  • A percentage will report a response to treatment because they improved (but actually, it had nothing to do with the remedy).
  • Another percentage will report a response which doesn’t actually exist, because they want to believe something has happened and persuade themselves it has.
  • Another percentage will report that they’ve improved based on an inaccurate assessment of their symptoms.
  • A further percentage will report a placebo effect, where they experienced a real improvement caused not by the treatment but because of their belief in it.

When you add up the false positive reports attributable to these errors, they more than account for why millions of people around the world today believe they have seen homeopathy ‘work’.

Like professional pilots, medical professionals are not immune to these errors. Indeed, because of the strength of their belief, and because they are exposed to countless patients telling them it’s worked every day, it's perhaps unsurprising that even a trained professional could come to believe that a non-existent dose of crushed Berlin Wall could in fact have some sort of effect.

So there we have it. A plausible, rational explanation as to why homeopathy works for so many people.

Truth is, it doesn’t.

They just think it does.