Most of those 11,000 donors genuinely wanted to help people by preserving access to the original canvas of a beautiful painting. And most of those 11,000 donors, if you asked, would say that a thousand people's lives are more important than a beautiful painting, original or no. But these people didn't have the proper mental habits to realize that was the choice before them, and so a beautiful painting remains in a British museum and somewhere in the Third World a thousand people are dead.

If you are to "love your neighbor as yourself", then you should be as careful in maximizing the benefit to others when donating to charity as you would be in maximizing the benefit to yourself when choosing purchases for a polar trek. And if you wouldn't buy a pretty picture to hang on your sled in preference to a parka, you should consider not helping save a famous painting in preference to helping save a thousand lives.

Not all charitable choices are as simple as that one, but many charitable choices do have right answers. GiveWell.org, a site which collects and interprets data on the effectiveness of charities, predicts that antimalarial drugs save one child from malaria per $5,000 worth of medicine, but insecticide-treated bed nets save one child from malaria per $500 worth of netting. If you want to save children, donating bed nets instead of antimalarial drugs is the objectively right answer, the same way buying a $500 TV instead of an identical TV that costs $5,000 is the right answer. And since saving a child from diarrheal disease costs $5,000, donating to an organization fighting malaria instead of an organization fighting diarrhea is the right answer, unless you are donating based on some criteria other than whether you're helping children or not.

Say all of the best Arctic explorers agree that the three most important things for surviving in the Arctic are good boots, a good coat, and good food. Perhaps they have run highly unethical studies in which they release thousands of people into the Arctic with different combination of gear, and consistently find that only the ones with good boots, coats, and food survive. Then there is only one best answer to the question "What gear do I buy if I want to survive" - good boots, good food, and a good coat. Your preferences are irrelevant; you may choose to go with alternate gear, but only if you don't mind dying.

And likewise, there is only one best charity: the one that helps the most people the greatest amount per dollar. This is vague, and it is up to you to decide whether a charity that raises forty children's marks by one letter grade for $100 helps people more or less than one that prevents one fatal case of tuberculosis per $100 or one that saves twenty acres of rainforest per $100. But you cannot abdicate the decision, or you risk ending up like the 11,000 people who accidentally decided that a pretty picture was worth more than a thousand people's lives.