is lacking, men either abandon their position or reserve their judgment.

Thus, a certain body of interrelated facts is built up, the
significance of which, in many fields at least, is apparent even to the
layman. Nor is it wholly beyond him to judge whether the results of
scientific investigations can be verified. An eclipse, calculated by
methods which he is quite unable to follow, may occur at the appointed
hour and confirm his respect for the astronomer. The efficacy of a
serum in the cure of diseases may convince him that work done in the
laboratory is not labor lost.

It seems evident that the several sciences do really rise on stepping
stones of their dead selves, and that those selves of the past are
really dead and superseded. Who would now think of going back for his
science to Plato's "Timaeus," or would accept the description of the
physical world contained in the works of Aristotle? What chemist or
physicist need busy himself with the doctrine of atoms and their
clashings presented in the magnificent poem of Lucretius? Who can
forbear a smile--a sympathetic one--when he turns over the pages of
Augustine's "City of God," and sees what sort of a world this
remarkable man believed himself to inhabit?

It is the historic and human interest that carries us back to these
things. We say: What ingenuity! what a happy guess! how well that was
reasoned in the light of what was actually known about the world in
those days! But we never forget that what compels our admiration does
so because it makes us realize that we stand in the presence of a great
mind, and not because it is a foundation-stone in the great edifice
which science has erected.