owever, for it is a necessary
law of the mind that we shall begin to make opinions and judgments on a
subject as soon as we become acquainted with it. The only safeguards
are, in the first place, to keep these preliminary judgments tentative
and fluid, and in the second, to keep them to one's self until there is
some need of expressing them. The path to wisdom in action is through
open-mindedness and caution.

When one has to refute an argument in which there is faulty
generalization, it is often easy to point out that its author had no
sufficient time or chance to make observations, or to point out that the
instances on which he relied are not fair examples of their class. In
practice the strength of an argument in which this error is to be found
lies largely in the positiveness with which it is pronounced; for it is
human nature to accept opinions which have an outward appearance of
certainty.

A not uncommon form of faulty generalization is to base an argument on a
mere enumeration of similar cases. This is a poor foundation for an
argument, especially for a probability in the future, unless the
enumeration approaches an exhaustive list of all possible cases. To have
reasoned a few years ago that because Yale had beaten Harvard at rowing
almost every year for fifteen years it had a permanent superiority in
the strength and skill of its oarsmen would have been dangerous, for
when the years before the given period were looked up they would have
shown results the other way. And an enumeration may run through a very
long period of time, and still in the end be upset.

To an inhabitant of Central Africa fifty years ago, no fact probably
appeared to rest on more uniform experience than this, that all human
beings are black. To Europeans not many years ago, the proposition, 'All
swans are white,' appeared an equally unequivocal instance of uniformity
in the course of nature. Further experience has proved to both that they
were mistaken; but they had to wait fifty centuries for this experience.
During that long time, mankind believed in an uniformity of the course
of nature where no such uniformity really existed.[37]

Unless you have so wide and complete a view of your subject that you can
practically insure your enumeration as exhaustive, it is not safe to
reason that because a thing has always happened so in the past, it will
always happen so in the future. The notorious difficulty of proving a
negative goes back to t