nfused state, and hypotheses crowd one
another thick as a swarm of bees. It cannot be otherwise. In physics
we investigate the movements of molecules, in chemistry the
development of molecules from atoms, and if the theory of light waves
should not be correct we have no absolute knowledge that we even see
these interesting things. The lapse of time produces a very thin crop
of final truths of last instance. In geology we are in a still more
embarrassing situation for we are here involved in the study of
preceding epochs in which, as a matter of fact, neither we ourselves
nor any other human being ever existed. Here there is much labor spent
in the harvesting of truths of last instance, and they are a scanty
crop withal.

The second division of knowledge is occupied in the investigation of
living organisms. In this field the changes and causalities are so
complex that not only does the solution of each question bring about
the rise of an unlimited number of new questions, but the solution of
each of these separate new questions depends upon years, frequently
centuries, of investigation, and can then be only partially completed.
So that the need of systematic arrangement of the various
interrelations continually surrounds the final truths of the last
instance with a prolific and spreading growth of hypotheses. Look at
the long succession of progressive steps from Galen to Malpighi
necessary to establish correctly so simple a thing as the circulation
of the blood of mammals, yet how little we know of the origin of blood
corpuscles and how many mistakes we make in, for example, rationally
connecting the symptoms and cause of a disease. Besides there are
frequently discoveries like those of the cell which compel us to
entirely revise all hitherto firmly established truth of the last
instance in biology, and to lay numbers of such truths aside for good
and all. He who would therefore in this science undertake the
proclamation of absolute and immutable truths must be content with
such platitudes as the following: "All men must die; all female
mammals have mammary glands, etc." He will not even be able to say
that the greater animals digest their food by means of the stomach and
bowels and not with the head because the centralised system of nerves
in the head is not adapted to digestion.

But things are worse with regard to final truths of last instance in
the third group of sciences--the historical. These are concerned with