ure. These also have
their inner mechanism and their store of force to set that mechanism
going. The ultimate problem of physical science is to reveal this
mechanism, to discern this store, and to show that from the combined
action of both, the phenomena of which they constitute the basis,
must, of necessity, flow.

I thought an attempt to give you even a brief and sketchy illustration
of the manner in which scientific thinkers regard this problem, would
not be uninteresting to you on the present occasion; more especially
as it will give me occasion to say a word or two on the tendencies and
limits of modern science; to point out the region which men of science
claim as their own, and where it is futile to oppose their advance;
and also to define, if possible, the bourne between this and that
other region, to which the questionings and yearnings of the
scientific intellect are directed in vain.

But here your tolerance will be needed. It was the American Emerson,
I think, who said that it is hardly possible to state any truth
strongly, without apparent injustice to some other truth. Truth is
often of a dual character, taking the form of a magnet with two poles;
and many of the differences which agitate the thinking part of mankind
are to be traced to the exclusiveness with which partisan reasoners
dwell upon one half of the duality, in forgetfulness of the other. The
proper course appears to be to state both halves strongly, and allow
each its fair share in the formation of the resultant conviction. But
this waiting for the statement of the two sides of a question implies
patience. It implies a resolution to suppress indignation, if the
statement of the one half should clash with our convictions; and to
repress equally undue elation, if the half-statement should happen to
chime in with our views. It implies a determination to wait calmly
for the statement of the whole, before we pronounce judgment in the
form of either acquiescence or dissent.

This premised, and I trust accepted, let us enter upon our task. There
have been writers who affirmed that the Pyramids of Egypt were natural
productions; and in his early youth Alexander von Humboldt wrote a
learned essay with the express object of refuting this notion. We now
regard the pyramids as the work of men's hands, aided probably by
machinery of which no record remains. We picture to ourselves the
swarming workers toiling at those vast erections, lifting the