o show that these close subsidiary lines may
branch or vary again, and that those branches or varieties which are
best adapted to the existing conditions may be continued, while others
stop or die out. And so we may have the basis of a real _theory_ of
the _diversification_ of species; and here, indeed, there is a real,
though a narrow, established ground to build upon. But, as systems of
organic Nature, both are equally _hypotheses_, are suppositions of
what there is no proof of from experience, assumed in order to account
for the observed phenomena, and supported by such indirect evidence as
can be had. Even when the upholders of the former and more popular
system mix up revelation with scientific discussion,--which we decline
to do,--they by no means thereby render their view other than
hypothetical. Agreeing that plants and animals were produced by
Omnipotent fiat does not exclude the idea of natural order and what we
call secondary causes. The record of the fiat--"Let the earth bring
forth grass, the herb yielding seed," etc., "and it was so"; "let the
earth bring forth the living creature after his kind, cattle and
creeping thing and beast of the earth after his kind, and it was
so"--seems even to imply them. Agreeing that they were formed of "the
dust of the ground" and of thin air only leads to the conclusion that
the pristine individuals were corporeally constituted like existing
individuals, produced through natural agencies. To agree that they
were created "after their kinds" determines nothing as to what were
the original kinds, nor in what mode, during what time, and in what
connections it pleased the Almighty to introduce the first individuals
of each sort upon the earth. Scientifically considered, the two
opposing doctrines are equally hypothetical.

The two views very unequally divide the scientific world; so that
believers in "the divine right of majorities" need not hesitate which
side to take, at least for the present. Up to a time within the memory
of a generation still on the stage, two hypotheses about the nature of
light very unequally divided the scientific world. But the small
minority has already prevailed: the emission theory has gone out; the
undulatory or wave theory, after some fluctuation, has reached high
tide, and is now the pervading, the fully established system. There
was an intervening time during which most physicists held their
opinions in suspense.

The adoption of the undulator