Wednesday, June 15, 2016


This is a true story.  I have a friend who believes that eating peanut butter causes acne.  Maybe he’s right.  Throughout my adolescent years I suffered from acne, and I’m sure I ate more than my share of peanut butter.  So I’m not necessarily disagreeing with my friend about his conclusion.  Rather, I have a problem with his research methodology.

Here is my friend’s explanation for how he knows that peanut butter causes acne.  He admits that he has eaten peanut butter off and on his entire life (a very long life, I might add).  However, after something of a hiatus, recently he began eating peanut butter again on a regular basis and began experiencing facial acne.  He suspected that the peanut butter might be the culprit and stopped eating it.  The acne went away.  His conclusion: This proves that it was peanut butter that caused the acne.

What’s wrong with this analysis?  Well, there are many possible causes of acne, from changes in metabolism to changes in hormonal balance to changes in how one cares for one’s skin to changes in medications taken to any number of dietary factors besides peanut butter that might be a cause.  In short, my friend came to a conclusion based on a single trial and made no attempt to control for other possible factors. 

The design flaws in my friend’s “experiment” may be obvious to most of us.  However, let’s take a different case:  An individual has a life-threatening illness.  She prays to God asking that the illness be cured.  She recovers.  She attributes her recovery to the prayer.

Is this case really any different from the peanut butter/acne example?  In both cases there was a single instance of one event followed by another with no attempt to control for other factors that might have been the actual cause of the second event, and in both cases the individual concluded that there was a cause-and-effect relationship.  In short, the “methodology” in both cases is flawed in the same way.

The fundamental difference, though, is that there is widespread belief in the power of prayer.

There are better ways to design experiments.  You could run the acne experiment on many different people, half eating peanut butter and half not, while controlling for other factors such as age, gender, other dietary factors, etc., and note which group had a higher incidence of acne.  

You could do the same to test the power of prayer.  As a matter of fact, such studies have been done.  One well-designed study, for example, sponsored by the John Templeton Foundation, involved 1,800 cardiac patients.  The study, which was summarized in a 2006 New York Times article, failed to find any benefit of intercessory prayer.

You may quibble about such study’s methodology or argue that God refuses to be tested in that way.  But here’s what you should not do.  You should not point to a single case and say, for example, “Yes, but my uncle was really sick.  The doctors had given up on him, but we prayed and he recovered.  His doctors couldn’t explain it.  Even they were calling it a miracle.  Don’t tell me that prayer didn’t work.  I saw it work.”  This is simply falling back into the peanut butter/acne trap.  

Granted, the more unusual the situation, the more powerful can be the belief in the healing power of prayer.  But unusual things do happen.  The 5-year survival rate for individuals with metastasized lung cancer is around 4 percent.  If you knew someone who was diagnosed with lung cancer for whom you prayed and who survived, would you attribute that survival to prayer or simply to that person’s being part of the 4 percent?  Finally, consider this:  Why is it that no one ever prays asking God to regenerate an amputee’s lost limb?

© 2016 John M. Phillips


  1. I can not refute what you wrote. I guess the difference is FAITH in the existence of God who knows what is good for us. I question God almost daily and also get mad at Him many times. I just find when I read His word things straighten out in my mind. Some troubles we bring on ourselves, whether on purpose or by accident. We sew sew what we reap.

    1. Wanda, I agree that for someone who believes faith can have an effect on your state of mind. That doesn't work for me. But that doesn't mean that I feel lost or alone or that my life doesn't have meaning. I find meaning in my humanity and in my friends and loved ones.