64

Logic II 57

into his own. This society develops conceptions of its own. Bring
together the men from widely different departments, -- say a
microscopical bacteriologist and an astronomer, -- and they
will hardly know what to say to one another; for neither has seen
the world in which the other lives. True, both use optical instruments;
but the qualities sought striven for in a telescopic lens objective are of no
consequence in a microscopic objective; and all the subsidiary
parts of telescope and microscope are constructed on principles
utterly foreign to one another, -- except their stiffness.

Here, then, are natural classes of sciences all sorted out for
us in nature itself, so long as we limit our classification
to actually recognized sciences. We have only to look over
this list of scientific periodicals and the list of scientific societies
to find the Families of science ready named. I call such classes Families
because Agassiz tells us that it is the Family which strikes the
observer as first glance. To make out then genera and
especially the species closer examination is requisite; while the knowledge
of orders, classes, and branches calls for a broader acquaintance
with science.

{Marginal note in different handwriting: [diff?] [parent?] [diff?] [type?] [copy?]}