fined. For the sake of clearness I will
use the simplest illustrations and, avoiding as much as possible the
difficulties of technical terms, will use language easily to be understood
by every one. In some cases the words will indeed have a technical meaning
and it will be necessary to exercise great care against the danger of
giving false impressions; for clear ideas are essential to sound thinking.
As a matter of fact our common daily speech is ill adapted for the precise
expression of thought; even so-called "scientific" language is often too
vague for the purpose and requires further refining. Some may say that it
is useless and unnecessary to lay so much stress on correct thinking and
precise expression; that it has no practical value; for they say that
"business" language is good enough to "talk business," or to put
"something over" the other fellow. But a little explanation will show that
precision is often of the greatest importance.

Humanity is a peculiar class of life which, in some degree, determines its
own destinies; therefore in practical life _words_ and _ideas_ become
_facts_--facts, moreover, which bring about important practical
consequences. For instance, many millions of human beings have defined a
stroke of lightning as being the "punishment of God" of evil men; other
millions have defined it as a "natural, casual, periodical phenomenon";
yet other millions have defined it as an "electric spark." What has been
the result of these "non-important" definitions in practical life? In the
case of the first definition, when lightning struck a house, the
population naturally made no attempt to save the house or anything in it,
because to do so would be against the "definition" which proclaims the
phenomenon to be a "punishment for evil," any attempt to prevent or check
the destruction would be an impious act; the sinner would be guilty of
"resisting the supreme law" and would deserve to be punished by death.

Now in the second instance, a stricken building is treated just as any
tree overturned by storm; the people save what they can and try to
extinguish the fire. In both instances, the behavior of the populace is
the same in one respect; if caught in the open by a storm they take refuge
under a tree--a means of safety involving maximum danger but the people do
not know it.

Now in the third instance, in which the population have a scientifically
correct definition of lightning, they provide their houses