"A little learning is a dangerous thing," Alexander Pope wrote in An Essay on Criticism nearly four hundred years ago.  He got that right.  People who make decisions or engage in actions based on partial knowledge sometimes do more damage than those who operate on the basis of total ignorance.  Far too many individuals proceed as if they were experts when, in fact, they know little about what they are doing or saying.  The fault ranges from the so-called geniuses who have wrecked the global economy to the homeowner who tries to repair his own plumbing to many of the people who post advice or information on websites (including, unfortunately, sometimes on this one, until I catch it and delete it).

In my experience, one the most difficult sentences for human beings to utter is "I don't know."  Such an admission may be wrenched out of people, perhaps, when they are totally ignorant of something.  On the other hand, people who have only partial knowledge of some subject are reluctant to admit that they do not know everything about it.  Most of us have, for example, encountered the self-appointed "computer expert" who hits a snag, pushes keys randomly, manages (by sheer luck) to find the right combination, and then proclaims (with a knowing smile), "There.  That's how it's done."  To such individuals, trial-and-error (even at the risk of crashing the entire system) is preferable to saying, "I don't know."

"A little learning" is especially dangerous among teachers – not only those who are professional teachers but all of us who, at some time or another, set ourselves up as the tutors of others who know less than we do.  (Note to parents:  This is the role you play with your children even if, when they become teenagers, they are convinced that they know more than any living adult.)  When we know little, we open up a multitude of dangers.  Among them is the chance that we will "make stuff up" to cover our ignorance.  That act, in turn, introduces two hazards – first, that the learner she will believe our invention and perpetuate the fabrication; second, that the teacher will be found out and will lose credibility.

Of these two consequences, the greater by far is that we tend to believe and act upon the ideas of people who know little but who come across convincingly as knowing more.  Even though we are reluctant to admit it, we are all gullible to some extent.  A multibillion-dollar marketing industry is evidence that our thoughta and actions can be influenced by half-truths (which is another way of saying, "a little knowledge").  Every day, millions of people make purchasing decisions based on advertising, not on in-depth research.  The consequences are insignificant for routine purchases (who is going to conduct a comprehensive, comparative study of every household item that he or she buys?).  However, they could be critical and costly if the purchase is a major appliance, an automobile, or a home.

The baneful results of a little knowledge extend beyond daily business transactions, however.  Reports of the causes of the current economic crisis reveal how people who were so-called experts (bankers, brokers, and so on)manipulated financial instruments about which they had little knowledge and sold mortgages to people who, in turn, had little knowledge of what they were signing.  People wearing blinders led the blind toward an economic precipice.  As we fell off the cliff, everyone was blaming everyone else for being greedy.  That fault-finding is true in part, but attributing the crisis exclusively to greed is itself an example of little knowledge (little understanding) of what actually happened.  The economic meltdown was caused as much by people who didn't know what they were doing (but did it anyway) as it was by unmitigated greed.  One reason, of course, why it is so difficult to unravel the mess is that many of the people who are now charged with doing so still have little knowledge of how to proceed, though they are obliged to act as if they do.

The negative consequences of having a little knowledge (but pretending that we have a comprehensive command of whatever the subject may be) extends far beyond the relatively tangible area of economics.  A little knowledge is dangerous in any realm of thought or ideas.  Prejudices, for example, are based as much on insufficient knowledge as they are on the inherent meanness of the individual who holds the prejudice.  A prejudiced individual reaches a general conclusion about a group of people (or something else) based on either no knowledge or knowlege of only a few indiduals in the group.  In other words, whenever we use a small number of observations (even if they are facts) to reach a sweeping conclusion or generalization, we are basing an idea on little knowledge.

Of course, we all do this.  It is extremely difficult, if not impossible, to know everything about anything.  It's therefore rather curious that we feel somehow compelled to convince ourselves and others that we know more about something than we really do, when – somewhere deep in our brains – we are fully aware that we know less than we pretend to know.  We are comfortable with certainty and fearful of uncertainty.  (Someone else can debate this "chicken or egg" question.)  What we can do to avoid the dangers of too little knowledge is to listen more closely to the voice in our heads that says, "You don't know as much as you think you do."

In something of a paradox, the key to making wise decisions and to acting intelligently may lie more in recognizing how little we do know than in knowing more.  That is perhaps why Socrates said that "the beginning of wisdom is the discovery of one's own ignorance."  He did not say that wisdom is ignorance, nor even that an awareness of ignorance constitutes wisdom.  He asserts only that being aware of the limitations of our knowledge puts us on the path to wisdom.

With such an awareness, we become teachable.  It is a truism, for example, that the older students in my night class are almost always more teachable than the younger ones are.  One reason is, of course, that the older students have had more experience.  The real difference, however, may be that the older students have discovered that there are significant gaps in their knowledge, whereas their younger counterparts think that having a high school diploma means that they are prepared for adult life.  These younger students expect that they can get by with more of the same, preferably acquired by osmosis.  They don't learn otherwise until they flunk a placement test, fail a diagnostic test in a given course, or perhaps wake up at midsemester flunking every subject.  Then they either become teachable and willing to learn or decide to muddle on by faking it with what little knowledge they have.  Unfortunately, many choose the latter, beginning on a lifelong path of pretension, one fraught with the dangerous pitfalls of "a little knowledge," some of them possibly catastrophic:  "Gee, I didn't know what a variable rate mortgage could cost me each month."

We don't hear much anymore about "intellectual curiosity" – the desire to learn more than we know about everything we can, regardless of whether we can foresee its usefulness.  Rather, we focus on whatever, in our perception, we need to know to get us by.  Anything beyond our small body of useful knowledge (again, according to our view of what will be useful) is dispensable.  A prerequisite for this valuable attribute of intellectual curiosity is the willingness to go beyond what we need to know.  That may seem like an abstract ideal for eggheads (and it probably is, to some extent), but it's also a survival tool.  We never know when that little piece of extra know-how will work to our advantage.

Admittedly, we must sometimes settle for only a little knowledge.  For example, someone who is learning to use a complex computer program may master only the basic operations and learn others only on an as-needed basis.  This little knowledge may be sufficient.  That's okay, as long as we admit our limitations and don't set ourselves up as experts when we are still novices.  Furthermore, as we are learning the program, it might be a good idea to learn at least one new operation each day – just in case.  For those with intellectual curiosity, learning something new is in itself gratifying.  For anyone else, who knows?  That little bit of extra skill may come in handy someday.

Putting aside whether a little learning is dangerous, we can at least acknowledge that a little learning is a dead-end street.  There is no exuse for remaining ignorant of something when we have the opportunity to become at keast somewhat knowledgeable about it.  The reasons we give for our little knowledge are never admirable.  The most common is that it isn't worth knowing.  That is insufferable arrogance, for it proclaims that we are so powerful that we can judge, from the infinite amount of available knowledge, what is worthwhile and what is not.  While the admission of one's own ignorance may be an admirable quality, akin to humility, pride in one's ignorance is not.  It is a reprehensible trait, one that many self-proclaimed anti-intellectuals use as a cover for their own mental laziness.

The most damaging kind of "little knowledge" is not in knowing little, nor even in believing that we know more than we do (though that is damaging enough), but in taking so much pride in the little we know that we never seek to know any more,