Haeckel's Evolutionist Position

The average type of the Theory of Descent of the older or orthodox school,

which still lingers in the background with its Darwinism unshaken, is that

set forth by Haeckel, scientifically in his "Generelle Morphologie der

Organismen" (1866), and "Systematische Phylogenie" (1896), and popularly

in his "Natural History of Creation" and "Riddles of the Universe," with

their many editions. We may assume that it is well known, and need o ly

briefly recall its chief characteristics. The "inestimable value," the

"incomparable significance," the "immeasurable importance" of the Theory

of Descent lies, according to Haeckel, in the fact that by means of it we

can explain the origin of the forms of life "in a mechanical manner." The

theory, especially in regard to the descent of man from the apes, is to

him not a working hypothesis or tentative mode of representation; it is a

result comparable to Newton's law of gravitation or the Kant-Laplace

cosmogony. It is "a certain historical fact." The proofs of it are those

already mentioned.



What is especially Haeckelian is the "fundamental biogenetic law,"

"ontogeny resembles phylogeny," that is to say, in development, especially

in embryonic development, the individual recapitulates the history of the

race. Through "palingenesis," man, for instance, recapitulates his

ancestral stages (protist, gastraead, vermine, piscine, and simian). This

recapitulation is condensed, disarranged, or obscured in detail by

"cenogenesis" or "caenogenesis." The groups and types of organisms exhibit

the closest genetic solidarity. The genealogical tree of man in particular

runs directly through a whole series. From the realm of the protists it

leads to that of the gastraeadae (nowadays represented by the Coelentera),

thence into the domain of the worms, touches the hypothetical "primitive

chordates" (for the necessary existence of which "certain proofs" can be

given), the class of tunicates, ascends through the fishes, amphibians and

reptiles to forms parallel to the modern monotremes, then directly through

the marsupials to the placentals, through lemuroids and baboons to the

anthropoid apes, from them to the "famous Pithecanthropus" discovered in

Java, out of which homo sapiens arose. (The easy transition from one

group of forms to another is to be noted. For it is against this point

that most of the opposition has been directed, whether from "grumbling"

critics, or thoroughgoing opponents of the Theory of Descent.)



Haeckel's facile method of constructing genealogical trees, which ignores

difficulties and discrepant facts, has met with much criticism and

ridicule even among Darwinians. The "orator of Berlin," Du Bois-Reymond,

declared that if he must read romances he would prefer to read them in

some other form than that of genealogical trees. But they have at least

the merit that they give a vivid impression of what is most plausible and

attractive in the idea of descent, and moreover they have helped towards

orientation in the discussion. Nor can we ignore the very marked taxonomic

and architectonic talent which their construction displays.