Economists are notorious for emphasizing the selfishness of human motives.  The immortal words of Adam Smith are the gateway drug:

is not from the benevolence of the butcher, the brewer, or the baker,
that we expect our dinner, but from their regard to their own interest.
We address ourselves, not to their humanity but to their self-love, and
never talk to them of our own necessities but of their advantages.

From here, it is a short trip to the tragedy of the commons, kidney markets, public choice theory, and hundreds of other stories that revolve around the selfishness of man.  Economists eat this stuff up.

Yet despite everything, it is child’s play to make a room of economists howl at popular stories of self-interest.  Just get the economists’ attention, then deadpan, “Today I donated blood because I want to make sure there will be enough blood for me if I ever need it.”  Economists will climb over each other to object, “What are the odds your tiny donation will matter?”  “So you’re going to single-handedly keep the blood bank from running dry?  Yeah right.”  You’ll provoke similar reactions if you declare, “I joined the army to preserve my freedom,” “I voted for Reagan because I couldn’t afford to pay Carter’s taxes” or “I give to charity in case I need charity one day.” 

Each of these stories appeals to self-interest, but economists almost uniformly reject them as absurd.  Why?  Because they ignore another beloved economic insight: the logic of collective action.  When actors have a small effect on big social outcomes, and their only incentive to act is the big outcome itself, selfishness urges them to stand down, twiddle their thumbs, free ride, and yawn “Let someone else do it.”

Superficial observers will see further evidence that economists can’t shut up about selfishness.  But on reflection, the logic of collective action is compelling evidence for the power of altruism.  How so?  Because actual human beings often engage in collective action despite the strong selfish case for inaction!  Many people give blood without the slightest recompense.  Many people voluntarily join the army when they see their country in danger, despite high risk and low wages.  Many people donate to charity even though eligibility for charity has nothing to do with their donation history.  If altruism is not their motive, what is?

Sure, true believers in ubiquitous selfishness can grasp at straws to protect their dogma.  Perhaps people donate blood for the free cookie, join the army because they might run for office one day, or give to charity in order to make business connections.  Or maybe millions of average joes are clueless enough to believe that the blood supply, the safety of the free world, and the availability of charity hinge on whatever they personally choose to do. 

Anything is possible, but that doesn’t mean that anything is plausible.  Once you grasp the logic of collective action, basic economics strongly supports a conclusion that economists rarely advertise: Genuine altruism is all around us.  Benevolence doesn’t explain why bakers bake bread for paying customers, but it does explain why blood donors give blood to strangers for free.