LANGUAGES AND CLASSIFICATION John Scales Avery November 3, 2017 Introduction As children, many of us have played the game, “20 Questions”. In this game, someone thinks of a word. Then the other players try to guess the word by asking questions, to which the answer can only be “yes” or “no”. Only 20 questions are allowed, but the word is almost always found correctly with this number of questions or less. This may seem surprising, unless we happen to know that 220 = 1, 048, 576, whereas the Second Edition of the 20-volume Oxford English Dictionary contains full entries for only 171,476 words in current use. Now I hope that the reader will forgive me if I indulge in some personal memories. Between 1950 and 1954, I was an undergraduate student of physics at the Massachusetts Institute of Technology. During this period, it occurred to me that an international language like Esperanto could be based on a system similar to “20 Questions”. The words in my invented language would be pronounceable, since they would alternate between vowels and consonants. The first few letters of the word would define the meaning in a rough way, and the following letters would specify the meaning more and more precisely. I believed that my invented international language would be very easy to learn because a learner would know the approximate meaning of a word from the first few letters. I wrote an article about my idea, and it was published in MIT’s Tech Engineering News. However, I later realized that no invented language, neither Esperanto, nor any other, would be able to compete as an international language with English, which happens to be very widely used at the precise moment that communication has become global. The use of English is backed by a huge literature, and by endless productions of the entertainment industry. Nevertheless, I still believe that my invented language has some interest, perhaps in the context of communication between humans and computers, especially when the computers are able to duplicate some of the functions of human intelligence. Fast forward more than half a century. In recent years I have become aware of Institute Professor Noam Chomsky’s pioneering work on the struc- ture of languages and on universal grammars, and I have even exchanged a few letters with him. Prof. Chomsky has rightly pointed out that human languages are qualitatively different from the languages of animals. As we have just noted, more than a hundred thousand English words are currently in use, and no animal language comes close to matching this vocabulary size. Moreover, animal languages do not have the grammatical structure or the 1 combinatorial flexibility of human languages. Prof. Chomsky also believes that the monumental linguistic abilities of humans were acquired very rapidly. This assertion implies that the human ability to quickly learn enormous numbers of words, as well as our innate tendency to use these words grammatically, can be traced back to a small number of mutations. I believe that we owe it to Prof. Chomsky’s stature to take this assertion seriously, and to examine, using the full armory of molecular biology, the question of how a few mutations could have produced our astonishing linguistic abilities. The 2014 Nobel Prize in Physiology or Medicine Once again, I hope that the reader will forgive me if I indulge in personal recollections. In 2014 I watched a television program in which Edvard Moser, May-Britt Moser, and John O’Keefe. the three winners of the 2014 Nobel Prize in Physiology or Medicine delivered their lectures in Stockholm. They had received the prize for their discovery of the specific neural networks in animal brains and in human brains, which allow us to learn and remember the branching decision-trees needed to find our way from place to place. I was already aware of Charles Darwin’s discussion of serial homologies in The Origin of Species. Darwin discusses cases where symmetrically repeated parts of an ancient progenitor have been modified for special purposes in their descendants. For example, the bones which fit together to form the brain case in reptiles, birds and mammals can be seen in fossil sequences to be modified vertebrae of an ancient progenitor. After discussing many examples, Darwin exclaims, “How inexplicable are these cases of serial homologies on the ordinary view of creation! Why should the brain be enclosed in a box composed of such numerous and extraordinarily-shaped pieces of bone?... Why should similar bones have been created to form the wing and leg of a bat, used as they are for totally different purposes, namely walking and flying? Why should one crustacean, which has an extremely complex mouth, formed of many parts, consequently have fewer legs; or conversely, those with many legs have simpler mouths? Why should the sepals, petals, stamens and pistils in each flower,though fit- ted for such distinct purposes, be all constructed on the same pattern?... On the theory of natural selection we can, to a certain extent, answer these questions.... An indefinite repetition of the same part is the common char- acteristic of all low or little-specialized forms... We have already seen that 2 parts many times repeated are eminently liable to vary... Consequently such parts, being already present in considerable numbers, and being highly vari- able, would naturally afford materials for adaption to the most different purposes.” Listening to the 2014 Nobel lectures, with Darwin’s views in mind, it occurred to me that a single mutation could cause the duplication in humans of the neural networks that all animals use in pathfinding. Once duplicated, one copy of these networks might afterwards be modified to serve as a foun- dation for human languages. There are many cases where a single mutation seems to have produced duplication of a structure. For example, we sometimes see the birth of an animal with two heads, or supernumerary legs. In the light of Professor Chomsky’s observation that human lan- guages are qualitatively different from animal languages, and his belief that modern humans acquired their astonishing linguistic abilities very rapidly, we ought to investigate the possibility that a single mutation caused a duplication of the pathfinding neural networks studied by Edvard Moser, May-Britt Moser, and John O’Keefe. We can then imagine that one copy of this duplicated pathfinding neural network system was modified to serve as the basis of human languages, in which the classification of words is closely analogous to the tree-like branching choice-pathways of an animal finding its way through a forest or maze.1 1Bold face is used here because the paragraph contains the central message of this book. 3 Contents 1 LINNAEUS AND BIOLOGICAL CLASSIFICATION 7 1.1 Linnaeus . .7 1.2 The language of Linnean classification . .8 1.3 Erasmus Darwin . 12 1.4 Charles Darwin . 13 1.5 Aboard the Beagle . 16 1.6 Tha Galapagos Islands . 17 1.7 The Origin of Species . 19 1.8 Classical genetics . 25 2 CHEMICAL COMMUNICATION 31 2.1 The structure of DNA . 31 2.2 The genetic code . 40 2.3 The language of molecular complementarity . 41 2.4 The flow of information between and within cells . 44 2.5 Nervous systems . 46 3 ANIMAL LANGUAGES 57 3.1 Communication of emotions . 57 3.2 Pheromones . 62 3.3 The waggle dance . 63 3.4 Parrots and crows . 64 3.5 Bushbabies . 67 3.6 Washoe, Nim Chimpsky and Koko . 67 4 OUT OF AFRICA 71 4.1 Early ancestors of modern humans . 71 4.2 Y-chromosomal DNA and mitochondrial DNA . 76 4.3 Exodus: Out of Africa . 82 4.4 Joseph Greenberg's classification of languages and DNA analysis 84 5 6 CONTENTS 5 PATHFINDING 91 5.1 The 2014 Nobel Prize in Medicine and Physiology . 91 5.2 Paths in cell differentiation . 99 5.3 Paths in package address systems . 99 5.4 Paths in the organization of computer memories . 101 5.5 Pattern abstraction . 102 5.6 Abstraction of concepts and natural laws . 112 6 THE EVOLUTION OF HUMAN LANGUAGES 127 6.1 Chomsky's assertion of rapid change . 127 6.2 Parse trees . 130 6.3 Garrod's hypothesis . 131 6.4 The FOXP2 gene and protein . 131 6.5 Slow evolutionary change; serial homologies . 132 6.6 The Neanderthal and Denisovan genomes . 133 7 CLASSIFICATION OF WORDS 139 7.1 Nouns . 139 7.2 Pronouns . 141 7.3 Adjectives . 144 7.4 Verbs . 145 7.5 Adverbs . 146 7.6 Conjunctions . 148 7.7 Prepositions . 148 7.8 Interjections . 149 7.9 Articles . 149 8 THE INFORMATION EXPLOSION 151 8.1 Can invented languages be pronounced? . 151 8.2 The evolution of consciousness . 152 8.3 Dreaming and intelligence . 152 8.4 Exponentially accelerating cultural evolution . 153 8.5 Agriculture . 154 8.6 Writing . 155 8.7 Printing . 156 8.8 An explosion of industry . 157 8.9 An explosion of communication . 158 8.10 An explosion of population . 160 8.11 Human emotions: an evolutionary paradox? . 162 8.12 Culture . 171 Chapter 1 LINNAEUS AND BIOLOGICAL CLASSIFICATION 1.1 Linnaeus During the 17th and 18th centuries, naturalists had been gathering information on thousands of species of plants and animals. This huge, undigested heap of information was put into some order by the great Swedish naturalist, Carl von Linn´e(1707-1778), who is usually called by his Latin name, Carolus Linnaeus. Linnaeus was the son of a Swedish pastor. Even as a young boy, he was fond of botany, and after medical studies at Lund, he became a lecturer in botany at the University of Uppsala, near Stockholm.