ay one day under a certain set of conditions, and
acting another way the next day under exactly the same conditions. Nor
does the physicist find the laws of mechanics holding good one day and
not the next.

The scientist, therefore, in his thinking brings order out of chaos in
the world. If we do not know the causes and relations of things and
events, the world seems a very mixed-up, chaotic place, where anything
and everything is happening. But as we come to know causes and
relations, the world turns out to be a very orderly and systematic
place. It is a lawful world; it is not a world of chance. Everything is
related to everything else.

Now, the non-scientific mind sees things as more or less unrelated. The
far-reaching causal relations are only imperfectly seen by it, while
the scientific mind not only sees things, but inquires into their causes
and effects or consequences. The non-scientific man, walking over the
top of a mountain and noticing a stone there, is likely to see in it
only a stone and think nothing of how it came to be there; but the
scientific man sees quite an interesting bit of history in the stone. He
reads in the stone that millions of years ago the place where the rock
now lies was under the sea. Many marine animals left their remains in
the mud underneath the sea. The mud was afterward converted into rock.
Later, the shrinking and warping earth-crust lifted the rock far above
the level of the sea, and it may now be found at the top of the
mountain. The one bit of rock tells its story to one who inquires into
its causes. The scientific man, then, sees more significance, more
meaning, in things and events than does the non-scientific man.

Each science has its own particular field. Zooelogy undertakes to answer
every reasonable question about animals; botany, about plants; physics,
about motion and forces; chemistry, about the composition of matter;
astronomy, about the heavenly bodies, etc. The world has many aspects.
Each science undertakes to describe and explain some particular aspect.
To understand all the aspects of the world, we must study all the
sciences.

=A Scientific Law.= By _law_ a scientist has reference to uniformities
which he notices in things and events. He does not mean that necessities
are imposed upon things as civil law is imposed upon man. He means only
that in certain well-defined situations certain events always take
place, according to all previous observations. The