Gaskell... had to keep his stately soldiers upright and uniformly oriented... by crafting the brain and spinal cord from an arthropod digestive tube, while forming a completely new gut below. ...Gaskell thought that his move would rescue the theory of linear progress, with its necessary transition of arthropod into vertebrate, from the absurdities of the old inversion theory.
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"Brotherhood by Inversion", p. 327Stephen Jay Gould
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Gaskell could not abide this indecorous version of his beloved linear progress theory. He could not bear to imagine that the grand procession from jellyfish to man, orchestrated by an ever-increasing mass of nervous tissue, once paused in its stately and orderly march toward human consciousness in order to execute a fancy little flip, a clever jig of inversion, just at the sublime and definitive moment of entrance into the vertebral home stretch.
Stephen Jay Gould
How ironic. In order to avoid the "nutty" theory of inversion, Gaskell invented the even odder notion of stomachs turning into brains with new guts forming below. No wonder then, that later biologists cast a plague on both speculative houses and opted instead for the obvious alternative: arthropods and vertebrates do not share the same anatomical plan at all, but rather represent two separate evolutionary developments of similar complexity from a much simpler common ancestor that grew neither a discrete gut nor a central nerve cord.
Stephen Jay Gould
Third Theory.—According to this theory, there is nothing in the whole Universe... that is due to chance; everything is the result of will, intention, and rule. It is a matter of course that he who rules must know. The Mohametan Ashariyah adhere to this theory, notwithstanding evident absurdities implied in it. ...The Ashariyah were therefore compelled to assume that motion and rest of living beings are predestined, and that it is not in the power of a man to do a certain thing or to leave it undone. ...It follows also from this theory, that precepts are perfectly useless, since the people to whom any law is given... can neither do what they are commanded nor abstain from what they are forbidden. ...According to this theory, it must also be assumed that the actions of God have no final cause. All these absurdities are admitted by the Ashariyah for the purpose of saving this theory.
Maimonides
Later evolutionary theorists of linear progress had to advance the overtly physical and historical claim that an ancestral lineage of arthropods actually turned over to become the first vertebrates (for the classical statement of the inversion theory, see William Patten, The Grand Strategy of Evolution, 1920).
Stephen Jay Gould
Arthropods and vertebrates share some broad features of general organization - elongated, bilaterally symmetrical bodies, with sensory organs up front, excretory structures in the back, and some form of segmentation along the major axis. But the geometry of major internal organs could hardly be more different... Arthropods concentrate their nervous system on their ventral (belly) side as two major cords running along the bottom surface of the animal. The mouth also opens on the ventral side, with the esophagus passing between the two nerve cords, and the stomach and remainder of the digestive tube running along the body above the nerve cords. In vertebrates, and with maximal contrast, the central nervous system runs along the dorsal (top) surface as a single tube culminating in a bulbous brain at the front end. The entire digestive system then runs along the body axis below the nerve cord.
Stephen Jay Gould
Gould, Stephen Jay
Govorov, Leonid
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