observed or apprehended; in the second, to be interpreted by inductive
and deductive reasonings, which are altogether similar in their nature
to those employed in science. In the one case, as in the other, whatever
is taken for granted is so taken at one's own peril; fact and reason
are the ultimate arbiters, and patience and honesty are the great
helpers out of difficulty.

But if scientific training is to yield its most eminent results, it
must, I repeat, be made practical. That is to say, in explaining to a
child the general phenomena of Nature, you must, as far as possible,
give reality to your teaching by object-lessons; in teaching him botany,
he must handle the plants and dissect the flowers for himself; in
teaching him physics and chemistry, you must not be solicitous to fill
him with information, but you must be careful that what he learns he
knows of his own knowledge. Don't be satisfied with telling him that a
magnet attracts iron. Let him see that it does; let him feel the pull of
the one upon the other for himself. And, especially, tell him that it is
his duty to doubt until he is compelled, by the absolute authority of
Nature, to believe that which is written in books. Pursue this
discipline carefully and conscientiously, and you may make sure that,
however scanty may be the measure of information which you have poured
into the boy's mind, you have created an intellectual habit of priceless
value in practical life.

One is constantly asked, When should this scientific education be
commenced? I should say with the dawn of intelligence. As I have already
said, a child seeks for information about matters of physical science as
soon as it begins to talk. The first teaching it wants is an
object-lesson of one sort or another; and as soon as it is fit for
systematic instruction of any kind, it is fit for a modicum of science.