Logic Loopholes

Our “thought life” can be put on a better footing if we are able to resist self-deception. Knowing some of the pitfalls we are subject to can help us plan defenses against deception.

Here are some ways that we human beings deceive ourselves and each other, along with a few suggested remedies.


  1. Humans love stories, especially those centered on a strong, identifiable character. We like to embroider truth to make a better story. Look for telltale signs of embroidery, and make allowances.
  2. Humans often allow themselves to be deceived as a way of avoiding threats. Ask yourself, Am I accepting this story because I dare not consider an alternative? Do not fear reassessing your values. Change may be inconvenient or even painful, but wallowing in ignorance is worse.
  3. We tend to think in terms of cause and effect. If we do not see a cause, our mind wants to invent one. Superstitions arise this way (“he suffered financial loss; it must be because he broke the letter chain”), and seeming miracle cures likewise crop up (“as soon as I cut Brussels sprouts from my diet, my headaches cleared up”). Look out for this post hoc thinking and replace it with further investigation to confirm truth.
  4. People are prone to using a prearranged explanation to shoot down problematic challenges to dearly held opinions. For example, people who believe in psychic powers often explain that those powers will not work when there are hostile unbelievers present. Do not be taken in by such ad hoc thinking, and demand proper evidence. But most of all, do not allow your own thinking to become distorted by this error.
  5. The Forer effect (named after the psychologist who investigated it) shows that people tend to apply things personally, even unconsciously. If we read a general horoscope prediction, our mind will work hard to believe that it fits, even if we are convinced that astrology is nonsense. Be aware of this tendency, and guard consciously against falling into it; sift evidence from others who have been so influenced.
  6. Analyzing a problem from a single viewpoint can be productive, but when we disallow alternatives, it’s called selective thinking. Leave room for consideration of other views, and by no means reject them without investigation.
  7. Particularly pernicious is the ad hominem fallacy, where we tend to accept or reject an idea because of the person who suggested it. Just because (fill in the blank) is untrustworthy does not mean that every idea he or she espouses is wrong. Conversely, an idea put forward by someone we like or respect is not necessarily right. Interestingly, almost all testimonial-style advertising relies on the ad hominem fallacy.