Still, ultimately, natural selection cares about only one thing (or, I should say, “cares”—in quotes—about only one thing, since natural selection is just a blind process, not a conscious designer). And that one thing is getting genes into the next generation. Genetically based traits that in the past contributed to genetic proliferation have flourished, while traits that didn’t have fallen by the wayside. And the traits that have survived this test include mental traits—structures and algorithms that are built into the brain and shape our everyday experience. So if you ask the question “What kinds of perceptions and thoughts and feelings guide us through life each day?” the answer, at the most basic level, isn’t “The kinds of thoughts and feelings and perceptions that give us an accurate picture of reality.” No, at the most basic level the answer is “The kinds of thoughts and feelings and perceptions that helped our ancestors get genes into the next generation.” Whether those thoughts and feelings and perceptions give us a true view of reality is, strictly speaking, beside the point. As a result, they sometimes don’t. Our brains are designed to, among other things, delude us.

Not that there’s anything wrong with that! Some of my happiest moments have come from delusion—believing, for example, that the Tooth Fairy would pay me a visit after I lost a tooth. But delusion can also produce bad moments. And I don’t just mean moments that, in retrospect, are obviously delusional, like horrible nightmares. I also mean moments that you might not think of as delusional, such as lying awake at night with anxiety. Or feeling hopeless, even depressed, for days on end. Or feeling bursts of hatred toward people, bursts that may actually feel good for a moment but slowly corrode your character. Or feeling bursts of hatred toward yourself. Or feeling greedy, feeling a compulsion to buy things or eat things or drink things well beyond the point where your well-being is served.

Though these feelings—anxiety, despair, hatred, greed—aren’t delusional the way a nightmare is delusional, if you examine them closely, you’ll see that they have elements of delusion, elements you’d be better off without.

And if you think you would be better off, imagine how the whole world would be. After all, feelings like despair and hatred and greed can foster wars and atrocities. So if what I’m saying is true—if these basic sources of human suffering and human cruelty are indeed in large part the product of delusion—there is value in exposing this delusion to the light.

Excerpted from Why Buddhism is True