While a graduate student, I had the great good fortune to know professor Marion J. Levy, of Princeton University. He heavily influenced my thinking on society and economy. In particular, he sensitized me to the pitfalls of relying upon good intentions and idealistic proclamations. I was working with Professor Levy at the time of the first Earth Day, a fine example of naïveté mixed with good intentions.

Many years later, he introduced Ramona and me to his Komondor livestock guard dogs. We found them an effective “predator-friendly” method of livestock protection.

We ran several hundred ewes and suffered significant predation. We heard many well-intentioned but ineffective or impractical recommendations, e.g., bring them down from rangeland and bed them by our house each night. No one who knows ranching would suggest this.

I still keep Levy’s two-volume set, Modernization and the Structure of Society (Princeton Univ. Press, 1966) by my home desk. If you understand that work, plus Thomas Sowell’s Knowledge and Decisions and Daniel Chirot’s How Societies Change, you have a good handle on how the world works. They will reduce your odds of suffering disappointment. They help avoid confusing pious hopes with prudent expectations.

Marion earned graduate degrees in both economics and sociology. He taught me that no one working in the policy arena is so valuable as a sociologist who understands economics or an economist who appreciates sociology.

In 1970 I moved from Indiana University to MSU and invited Marion out West several times. He always accepted and once told me he would bring his latest book, Levy’s Laws. He inscribed: “John, herewith my very best book. As ever, Marion.”

Mine is one of a limited edition of 300. Unfortunately, the hand-bound edition of Levy’s Laws totals eight small pages. It’s only one page on the web -- and it’s not abridged.

I recalled “Levy’s Law Number Four” when I read the New York Times article “Evangelical Leaders Swing Influence Behind Effort to Combat Global Warming.” Here’s his law regarding good intentions:

“Always pray that your opposition be wicked. In wickedness there is a strong strain toward rationality. Therefore there is always the possibility, in theory, of handling the wicked by outthinking them.... If good intentions are combined with stupidity, it is impossible to outthink them.”

The lead from the Times story of March 10 by Laurie Goodstein offers an excellent example of strongly motivated good intentions. It begins: “A core group of influential evangelical leaders has put its considerable political power behind a cause that has barely registered on the evangelical agenda, fighting global warming. These church leaders...argue that global warming is an urgent threat, a cause of poverty and a Christian issue because the Bible mandates stewardship of God’s creation.”

What motivated this? The president of the National Association of Evangelicals, The Rev. Ted Haggard, “had become passionate about global warming because of his experience scuba diving and observing the effects of rising ocean temperatures and pollution on coral reefs.”

They adopted a platform that included this statement: “Because clean air, pure water and adequate resources are crucial to public health and civic order, government has an obligation to protect its citizens from the effects of environmental degradation.”

I strongly agree with this principle and have worked to advance it for over 40 years. However, it is a mission statement, not a clear guide to policy. Why not? It offers no way to set priorities. Since we have real limits on the resources available to invest, it is irresponsible not to rank our investments in order of their effectiveness.

The researchers involved in the Copenhagen Consensus determined that global warming doesn’t make the cut. These internationally distinguished economists judged three projects addressing climate change (optimal carbon tax, the Kyoto protocol, and value-at-risk carbon tax) to be the least cost-efficient of the 17 proposals considered to address some of the world’s biggest challenges.

Economists specialize in efficiently allocating scarce resources among competing values. These Evangelicals aren’t burdened by this scarcity constraint. Through good intentions, they ignore it.

The world’s poor will suffer most if we follow the Evangelicals’ admonition. If we focus policy on arresting global warming, we are ethically obligated to consider the consequences for the poor.