Home / K. Effectiveness and individual responsibility / Part IND
"One person doesn't make a difference."
one person's purchase rarely decides on its own whether one more animal will be raised, but sometimes it does, and when it does it affects many at once. By expected-value reasoning, every purchase has a real average effect. Economists confirm the direction: less demand leads to less production. And even if the effect were zero, taking part in an unjust practice would still be a moral matter.
Note: this chapter also answers the technical version of the argument, "supply and demand don't work like that with meat", which was merged into it.
Short answer
It's true that the slaughterhouse doesn't change production because of one tray. But it does change because of many, and someone's purchase is always the one that triggers the next order. Since no one knows if it'll be theirs, the average effect of each purchase is real: a small chance of affecting many animals. Economists confirm that when demand falls, production falls, though less than proportionally. And even if it were zero, paying for something you consider unjust would still be taking part in it.
For children
Imagine a line to get into school, and the door only opens when ten children arrive. If you arrive and you're the tenth, the door opens because of you. You don't know if you'll be the tenth, but sometimes you will be. Shopping is similar: the store only orders more meat once it sells a certain amount, and sometimes it's your purchase that triggers the order. Every choice counts.
"If no one makes a difference alone, how does the demand of billions of people sustain production?"
Como pode aparecer
"You alone won't change anything."
"It's a drop in the ocean."
"The cow's already dead; I didn't kill it." (which is K2)
"As long as China eats meat, your lettuce makes no difference."
"How many animals did you save this year? Zero."
"Supply and demand don't work like that with meat: the slaughterhouse kills the same number anyway."
"If I don't buy it, the price drops and someone else buys it."
"Individual contributions don't reach the thresholds that change production."
"The problem is the system, not my plate." (which is B4)
The strongest version
"I alone won't change anything. If I stop eating meat, the slaughterhouse will kill the same number anyway."
Strongest version (steelman):
- P1An action is only obligatory if it makes a difference to the outcome.
- P2Meat production responds to orders in large batches, not to individual purchases.
- P3The chance that my purchase changes a batch is negligible.
- CSo my purchase makes no difference, and I have no obligation to change.
P2 is true: slaughterhouses and supermarkets don't adjust production for every tray sold. The problem lies in P3 and P1.
The argument is valid. Its soundness fails at P3, which confuses a small chance with a small effect, and at P1, which reduces morality to individual consequences.
Full answer
- a
Reconstruction and diagnosis
The argument has a correct starting point and a wrong conclusion. Production works by thresholds: the market only adjusts its orders when sales change by a certain amount.
Situation What happens Your purchase doesn't change the batch Zero effect, which is the most common case Your purchase is the one that changes the batch A large effect: a whole batch of animals Average across the cases The small chance multiplied by the large effect gives, roughly, an effect proportional to the purchase This is expected-value reasoning, set out by the philosopher Shelly Kagan in the paper Do I Make a Difference? (2011), which uses precisely the example of buying chicken. If the threshold is a thousand chickens, the chance your purchase is decisive is about one in a thousand, but when it is, it affects about a thousand chickens. The expected effect comes close to one chicken per chicken bought.
- b
Where the argument breaks
1. A small chance isn't a small effect.
P3 looks only at the chance and forgets the size of the effect when it happens. Multiplied together, they give a real average effect, as in the threshold example.
2. Aggregate demand is made of individuals.
If no purchase made a difference, the sum of all purchases wouldn't either, and production wouldn't respond to demand. But it does: that's how markets work, and it's why the industry invests in advertising.
3. Economics confirms the direction.
The effect of reduced demand on production is less than one-to-one, because the price falls a little and some consumption is picked up by other buyers. But the effect is positive: buying less leads to producing less. Economic estimates cited in the debate, such as those by Norwood and Lusk, fall below one animal fewer per animal not bought, and above zero.
4. The effect adds up over a lifetime.
A person eats thousands of meals. Even with an expected effect below one, the total over the years amounts to many animals.
5. There are effects beyond the purchase.
Choices are seen by others, influence the supply of plant options and change what seems normal. The impact of a worldview extends beyond the life of whoever adopts it.
6. Morality isn't reduced to causal effect.
Even if the purchase changed nothing, paying for a practice you consider unjust is taking part in it. No one would accept buying a product made with slave labor on the grounds that the factory would produce it anyway.
- c
Data and sources
Source What it says Note Kagan, *Do I Make a Difference?* (2011) In threshold cases, contributing has positive expected value; the central example is buying chicken Philosophy & Public Affairs, 39(2); author's page Norwood and Lusk, *Compassion, by the Pound* (2011) Estimates of how much production falls when demand for animal products declines Oxford University Press; exact values vary by product Nefsky, Consequentialism and the Problem of Collective Harm (2011) A critique of expected-value reasoning in cases of collective harm Shows the philosophical debate exists; used in (d) - d
The strongest counter-reply: not every case has a threshold
The most serious version, defended by philosophers such as Julia Nefsky, accepts expected value where there are clear thresholds, but doubts the meat supply chain works that way. Waste, stocks, exports and long-term contracts can absorb small variations, so many purchases may affect nothing at all. In that case, the probability of making a difference could be even smaller than the threshold reasoning assumes.
- e
Why the counter-reply doesn't reach the conclusion
It doesn't show the effect is zero.
It shows it's uncertain. If aggregate demand moves production, and it does, the average contribution of each purchase can't be nil.
Economists look at the aggregate.
Estimates of how production responds to demand already include stocks, waste and exports.
Nefsky herself doesn't conclude one may buy freely.
Her critique is of how the duty is justified, not of the duty itself: she argues that contributing to a bad outcome can be wrong even without making a difference.
The moral argument doesn't depend on the causal one.
Even with zero effect, paying for an unjust practice is still taking part in it, as in the slave labor case.
- f
Back to the moral question
The argument doesn't say animals don't matter; it says one person doesn't change the outcome. But each purchase has a real expected effect, and taking part in an unjust practice counts in itself. The moral question remains: if it's wrong to make animals suffer and die without need, why pay for it to happen?
Reasoning errors
Logical
Is the form valid?
Confusing probability with effect
Reverse fallacy of composition
Epistemological
Does the evidence support it?
Wrong model of the market
Moral
Is the criterion coherent?
Purely causal responsibility
Diffusion of responsibility
Biases
Scope insensitivity
Billions of animals are perceived as an abstraction, and a single animal seems to change nothing
Diffusion of responsibility
Guilt spread among many seems like no guilt at all
Motivated reasoning
The economic argument appears precisely where it excuses change
General literature on motivated cognition
Meat paradox
Powerlessness eases the tension between loving animals and eating them
Extrapolations
The principle being tested is: "if my contribution doesn't decide the outcome alone, I have no obligation".
If it applied to…VotingTap to see
No one would have a reason to vote
Almost everyone considers voting important
If it applied to…Buying products of slave laborTap to see
It would be acceptable, since the factory would produce them anyway
Almost no one accepts this
If it applied to…Polluting or litteringTap to see
One more piece of paper wouldn't make a difference
The collective outcome is made of these contributions
If it applied to…Donating to humanitarian causesTap to see
A small donation would have no value
The expected value of each donation is real
Contradictions
The chance of one vote deciding an election is tiny, and the same person considers voting important.
We do many things whose individual effect is small, because the combined effect matters.
Even knowing the factory would produce it anyway.
The same person understands that a product disappears from the shelves when no one buys it.
If the choice really were irrelevant, changing would make no difference to the chooser either.
What the argument gets right
What is true
There's truth in the argument. The meat supply chain doesn't respond to each purchase in isolation, and one person's effect is small next to an industry of billions of animals. It's also true that system changes, such as laws, technology and public policy, have a reach no individual choice can match, and deserve as much attention as each person's plate (K9).
But
But small isn't zero, and individual isn't irrelevant. The sum of choices is exactly what sustains the industry, and whoever takes part in it has a share, however small, in what it produces. Changing the system and changing one's own consumption don't compete: one usually feeds the other.
Connections
Usually comes before
Usually comes after
Go deeper in Questão de Ética
Chapters from the open-access collection A Journey Through Animal Ethics that discuss this argument in more detail:
- But Does Veganism Really Have a Practical Impact? Vol. IV, ch. 13
References
Philosophy
- Do I make a difference? *Philosophy & Public Affairs*, 39(2).
- Consequentialism and the problem of collective harm. Philosophy & Public Affairs, 39(4).
Economics
- Compassion, by the Pound: The Economics of Farm Animal Welfare. Oxford University Press.