If you base your political views on the assumption that people don’t tend to act in their self-interest, you are dooming yourself to chronic disappointment.

That’s not to say that most people are venal, evil, or contemptuous. They aspire to serve their fellow human beings and care about their welfare. Some live heroic lives of sacrifice — in roles ranging from missionary to Marine — while most others combine traditional careers with community service and personal acts of charity.

But self-interest is a powerful motivating force in human action. Understood broadly, it is not just an unavoidable human impulse but can indeed be harnessed to promote human progress.

If you have trouble stomaching the idea that human beings are hard-wired to prioritize the self, the familial, and the local above the collective, the foreign, and the faraway, run this simple thought experiment. Imagine two events occurred today. First, you heard on the radio that 78 people died in a natural disaster in Burma. Second, while chopping vegetables for your lunch, you accidentally cut off your little finger. Which event would cause you greater distress, motivate you to spend resources in response, and have the greatest long-term effect on your life?

Unless you are a saint, the honest answer would be that the loss of the finger was the more significant event. What if the Burmese death toll was 780, or 7,800, or 78,000? At what point would you say that the loss of your finger would truly pale in comparison to the overseas tragedy? Would you ever say it? And notice that I stacked the deck by choosing just one little finger. Imagine that you suffered the tragic death of a child or other close family member. Virtually no one could honestly say that quantity would trump familiarity in such an instance.

Of course, few truly believe that the lives of tens of thousands of foreigners aren’t morally worth as much as a finger, or the life of a single child. As a matter of fact, there are heroic people who risk life and limb every day to save others. Such sacrifice is noble. My point is simply that it rarely comes naturally.

Most of the time, human beings make decisions on the basis of what best meets their needs and those of their families and close friends. Most people are charitable, but they don’t give away the majority of their incomes. And when they are charitable, they tend to focus on causes closer to home, often with individuals or institutions with which they have a personal familiarity.

For example, most Americans who give to anti-poverty programs steer their dollars to institutions that primarily serve the needs of disadvantaged Americans. But poverty in the U.S., while certainly painful and worthy of redress, isn’t remotely comparable to the grinding poverty prevalent in, say, Africa or South Asia. The average American poor person is far healthier and safer than the average poor Bangladeshi or Zimbabwean. Objectively, the need for assistance is far greater overseas than within the U.S. Yet few Americans, of any religion or political persuasion, deploy their time and money accordingly.

These are immutable facts of human nature. Rage against them all you want to. It won’t change them. American conservatism – the political philosophy that used to be called liberalism, and still is in many other countries – begins with the principle that true progress requires an acceptance of reality. The reality here is that most people act with regard to their self-interest most of the time.

Fortunately, another reality to accept is that intentions don’t determine results. When governments use coercion to force people to act contrary to their personal choices, the results are often disappointing regardless of how well-intended the government program may have been. And in a market economy, individuals freely transacting business to mutual advantage tend to advance the common interest by promoting innovation, lower prices, better service, and economic opportunity.

Don’t take my word for it. Some dudes named John Locke and Adam Smith made this point a while back.

John Locke Foundation chairman John Hood is the author of Catalyst: Jim Martin and the Rise of North Carolina Republicans.