The word “paradox” gets applied to placebo a lot. Does the profusion of perceived paradoxes perpetuate placebo’s plentiful popularity? Perhaps. For the same reasons people like Escher’s illusions, we do seem to enjoy being baffled and bemused by placebo’s many apparent internal contradictions.
Emphasis on “apparent.”
This is the best-known placebo paradox: how can a placebo, which is biologically inert by definition, also have an effect? 🤯
But this problem isn’t as profound as it seems. It’s like hot sauce: all heat and no fire.
I have been fighting placebo hype for many years, and tackling the putative paradoxes has been on my to-do list for most of that time. In this post, I finally get around to pacifying the paradox beast … by revealing that it’s about as fierce as a baby panda.
But I will do that for members only. This is one of those paywalled posts. Non-members will eventually see this content in my main placebo article, but for now it’s just for PainSci members. JOIN NOW for USD $6/month or $60/year to unlock this post, its audio version, plus all pasts posts, and much more around PainScience.com. See more information about membership. ❐
The rest of this post is about 1500 words or five minutes of reading, and presents solutions to two common minor placebo paradoxes, plus the Big One: “how can it be inert if it has an effect?” I explain with cats and cucumbers.
Potent or powerless? We can’t have it both ways!
The most basic placebo paradox is that there seem to be so many reasons to think that placebos are “powerful.” The legend of placebo’s power began when Dr. Henry K. Beecher said it was powerful, in his 1955 paper (“The powerful placebo”).
And yet it’s so clear that placebo doesn’t actually resolve anything for most sick or injured people. In other words, if placebo were actually medically impressive, then purveyors of obvious snake oil (e.g. homeopathy) would have extraordinary success rates, the real thing, easily measured in a controlled test.
The solution: The effect of placebo isn’t actually “powerful” in the first place. It’s interesting, sure, but it’s definitely not medically amazing. There is even a legitimate ongoing debate about whether it exists in any meaningful sense at all; more on this below.
Is it unethical to prescribe a placebo… or unethical to withold it?
Since placebo is defined and widely understood as something that is biologically inert, it seems unethical to prescribe that thing. We shouldn’t give people fake medicine. But it is also unethical “not to use something that heals” (Newman). Cue the robot with the smoking circuitry pitifully crying, “Does not compute!”
Like most ethical collisions (and paradoxes), this arises more from imprecision in language.
The solution: Dispose of the delusion that witholding placebo’s modest powers is a serious ethical breach. The effect we call “placebo” can be “something that heals” in some limited sense — making people feel better is part of healing, after all — and yet it can still fail to meaningfully change the course of disease or recovery from trauma. The stakes here are low. It doesn’t matter much.
It also doesn’t have to come from a prescribed thing. The ethical conundrum is based on prescribing a bogus medicine, a physical and deceptive “placebo object” that is not what it appears to be — a sugar pill, a saline injection. We know today that the object is only the most obvious way to trigger what we call the placebo effect; there are many “contextual effects” in every therapeutic interaction, many things that have an effect on patients through a variety of psychobiological mechanisms. This makes the ethical problem mostly obsolete as well as less important: you don’t have to prescribe a bogus medicine to get the (modest) benefits of contextual effects. Indeed, you can’t even stop them.
“So many vows. They make you swear and swear. Defend the king, obey the king, obey your father, protect the innocent, defend the weak. But what if your father despises the king? What if the king massacres the innocent? It’s too much. No matter what you do, you’re forsaking one vow or another.”
Jamie Lannister, with one of my favourite bits of dialogue, in the entire Game of Thrones saga
ZOMG, how can something inert have an effect?!
The mother of all placebo paradoxes is baked right into the term “placebo effect”: how can a placebo be both biologically “inert” (the generally accepted definition) and have an “effect”? If it’s inert, then it cannot have effects. If it has effects, it cannot be inert!
This one has been tying people up in knots for decades, and you can read some seriously dense scientific literature about it.1 But I dare to propose that it’s not as profound as it looks. I think this paradox is about as serious as a finger trap, which you can get out of it in the same way: stop pulling in the direction that doesn’t work! Once again, it’s mostly just the messiness of language.
The solution: The “easy” way out of this one is to just argue that placebo does not in fact have any impressive effects to begin with — a hotly debated but defensible position.2
But that isn’t even necessary, because the idea that it’s a paradox is based on unnecessary absolutism.
The placebo effect is not one thing that is somehow, bafflingly, both inert and effectual. It is two things. First there is the placebo object, which is in fact inert (though not perfectly). Second, there is our psychological reaction to it. Psychological reactions to objects do not change their properties! That would be magic!
Cats are freaked out by cucumbers. Seriously. But no one thinks that means that cucumbers are “powerful.” We aren’t wringing our hands wondering how inert cucumbers can possibly have an effect on cats … while maintaining their “inert” credential! There is no cucumber-cat paradox. If the cucumber is inert, how can it have an effect on the cat? If it has an effect on the cat, how can the cucumber be inert? Well, because cucumbers have some secret freaky meaning to cats. And that’s the cat’s business, not a property of cucumbers — just as the placebo effect belongs to the affected, not the placebo.
In retrospect, the cat-cucumber analogy was probably the only thing I needed to debunk this paradox.
I have a sneaking suspicion that the alleged paradoxes of placebo are really just a way to exaggerate its mystique, to sustain and amplify the Legend of Placebo. Paradoxes are cool, and placebo is cooler because it has paradoxes!
But the coolest of them — the “inert vs. effect” paradox — is just an obvious "deepity," something that seems more profound than it is. On the one hand, the trivial interpretation of the paradox is correct, but not very interesting, just semantics. On the other hand, the most profound interpretation is just misleading hyperbole.
Placebo is not a glitch in the Matrix or a rip in the space-time continuum: it’s just that humans are complex and messy and our emotions and perceptions can be influenced by things that are medically impotent. Duh.
From the conclusion of an article in the journal Theory & Psychology:
Explaining emotion responses and placebo responses in terms of propositional attitudes and mental representations (or mental models), throws up the paradoxes we encountered in the first two sections of this article. Moving to an EM-Cog account of attitudinal content is to move to an examination of attitudinal contents as occasioned, indexical, endogenously produced practical phenomena, which are available for analysis to both lay and professional analysts.
We have also seen the need to go beyond attitudinal accounts and overcome the instinct–cognitive dichotomy. We now acknowledge that between instinctive, physiological responses to causal stimuli on the one hand, and attitudinal responses on the other, there is a mode of responsiveness to loci of significance in the lifeworld that is not stimulus–response, because it is intentional, meaningful, and indexical, yet nor is it attitudinal (and representational). While existential phenomenology and Ecological Psychology propose formal–analytic accounts of this mode of responsiveness, I recommend that here too we might instead pursue the policies proposed by ethnomethodology and undertake ethnomethodologically informed (sensory) ethnographies so that we might recover the ways in which members make available-to-observation and acknowledgement, to lay and professional analysts, their nonattitudinal responsiveness to meaningful loci of significance in the lifeworld.
For instance, see Kienle and Hróbjartsson. The ensuing debate has been fruitful over the last twenty years, and many experts are convinced these days that placebo isn’t “powerful” after all — not even for the entirely subjective outcome of pain — and that Henry “The Powerful Placebo” Beecher was substantially wrong. For an excellent 2015 summary, see Brissonnet, who concludes:
So, then! Placebo, are you there? The placebo object is certainly there! It will be irreplaceable for the foreseeable future in carrying out the controlled clinical studies that are essential to medical research. As for the effect of the placebo, that doesn’t exist. As for the effect “called” placebo, if its existence is undeniable albeit limited, it would be better to simply name it “contextual effect” in order to better understand its true nature and to make its magical connotations disappear.