There is surely a great deal more to be read off from

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[[p_153]] as evidence of phylogenetic history. There is surely a great deal more to be read off from the phenomena of homology than the biologists have yet dreamed of. In terms of this discrimination between class and group, the aggregate of vertebrae in the spinal cord is a class, inasmuch as every vertebra shares certain features with every other. We may say that every vertebra is built upon the same ground plan. But the aggregate is also a group in the sense that each vertebra is a modulation of the vertebra preceding it in the for-and-aft sequence. There are, however, interesting discontinuities of modulation between the thoracic and lumbar. In addition, the vertebrae are interrelated in a third way so that all fit together and work together as part of a single whole.
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What was said above about three ways in which the vertebrae are related is a small piece of that larger mystery, the organization of the biosphere. Thus, when we look behind the word ―structure,‖ we encounter fragments of paradigm, of how the larger fabric is put together. There is, however, a more problematic aspect of our notion of ―structure,‖ which must be stressed. As we scientists use the word, it promotes in us a false notion that the more concrete details subsumed under a given name structure are somehow really components in that structure. That is, we easily come to believe that the way we dissected the real world in order to make our description was the best and most correct way to dissect it. Chemists may say that all halogens (that genus of elements that includes flouring and chlorine and so on) share certain formal characteristics in modulated degree, and therefore constitute a ―group‖ and, further, that such groups of elements can be set together to make the periodic table of elements. We may object that this is quite unreal that these are but formal resemblances and the classification of the items is an artefact, an act of the chemist and not an act of nature. But criticism of this kind is often inappropriate in biology. If we as biologists think we are using the word ―structure‖ as a physicist or chemist might, we run the risk of overcorrecting for that error. [And yet we may also make the opposite error of asking too little of our biological descriptions, believing that if they seem to fit that is all that must be asked.] It is true, of course, that there are no names in a purely physical universe and the stars have names only because men have named them. Even the constellations exist only as men have seen constellations into the [[p_154]] heavens. Similarly, the structural statements of physicists and chemists refer only to structure immanent in their theories, not in the physical world. But that is not so in the biological world. In that world, in the world of communication and organization, the exchange of news and messages is an essential component of what goes on. The anatomy of the spinal cord is determined in embryology by genetic processes and messages from the DNA and from other growing organs, and these messages are necessarily summative. They depend upon
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  • Fall '19
  • Gregory Bateson

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