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Logic II 46

whose notions views of classification are most opposite
to those of Agassiz are saturated with metaphysics in
its dangerous form, -- i.e. the unconscious form, -- to
such an extent that what they say upon this subject
is rather the expression of a traditionally absorbed
fourteenth century metaphysics than of scientific
observation.

{Marginal note: ^* Essay on Classification. 4th. 1857. p.170. The reader will perceive by the date, that these ideas were put forth at a somewhat inauspicious moment.}

The definitions of Agassiz are as follows:
It would be useless for our purpose to copy the definitions
of Agassiz^* had he not expressed them in the briefest terms,
as follows:

Branches are characterized by the plan of structure;

Classes, by the manner in which that plan is extended, as far
as ways and means are concerned; ["Structure is the watchword for the
recognition of classes." p. 145]

Orders, by the degrees of complication of that structure;
["The leading idea . . is that of a definite truth among them", p. 151]

Families by their form, as determined by structures; ["When