look back with a regretful longing towards something which they have
outgrown, and left behind.

I propose this morning to answer this question, just as simply, as
frankly, as I can; to treat it with all reverence, with all
seriousness, and try to make clear what it is that the world has lost
as the result of the advances of modern knowledge, and what, if
anything, it has gained.

But while I stand here, on the threshold of my theme, and before I
enter upon its somewhat fuller discussion, I wish to urge upon you two
or three considerations.

It is assumed, by the people who ask this question, that, if we do take
away anything, we are under obligation straightway to put something in
its place. I wish you to consider carefully as to whether this position
is sound. Suppose, for example, that I should discover that some belief
that has been held in the past is not well founded, not true. Must I
say nothing about it because, possibly, I may not have discovered just
what is true?

To illustrate what I mean: Prince Alphonso of Castile used to say, as
he studied the Ptolemaic theory of the universe, that, if he had been
present at creation, he could have suggested a good many very important
improvements. In other words, he was keen enough to see that the
Ptolemaic theory of the universe was not a good working theory. Must he
keep still about that because, forsooth, he was not able to establish
another theory of the universe in its place?

Do you not see that the criticism, the testing of positions which are