Page:Public Opinion (Lippmann).djvu/167

Rh And, as he added in another place, "your acting thus may in certain special cases be a means of making it securely true in the end." Yet no one would have insisted more than he, that, so far as we know how, we must avoid substituting the goal for the starting point, must avoid reading back into the present what courage, effort and skill might create in the future. Yet this truism is inordinately difficult to live by, because every one of us is so little trained in the selection of our samples.

If we believe that a certain thing ought to be true, we can almost always find either an instance where it is true, or someone who believes it ought to be true. It is ever so hard when a concrete fact illustrates a hope to weigh that fact properly. When the first six people we meet agree with us, it is not easy to remember that they may all have read the same newspaper at breakfast. And yet we cannot send out a questionnaire to 816 random samples every time we wish to estimate a probability. In dealing with any large mass of facts, the presumption is against our having picked true samples, if we are acting on a casual impression.

And when we try to go one step further in order to seek the causes and effects of unseen and complicated affairs, haphazard opinion is very tricky. There are few big issues in public life where cause and effect are obvious at once. They are not obvious