In two early paragraphs from her book titled Silent Spring, Rachel Carson employs the rhetorical techniques of appeal to authority and use of statistics to strengthen her arguments. Thus, in the paragraph that begins “Another factor in the modern insect problem,” Carson is careful to mention “British ecologist Charles Elton in his recent book The Ecology of Invasions.”
The reference to Elton is an “appeal to authority” in a number of subtle ways and has a number of distinct effects. It is important, for instance, that Elton is mentioned by name. If Carson had simply cited “recent authorities,” her argument would seem far less persuasive. Carson’s decision to mention Elton by name gives any interested reader a chance to check Elton’s credentials, assess his expertise, and determine the likely value of his claims.
Elton, as it happens, was an important zoologist who taught for many years at Oxford University. His book The Ecology of Invasions was published by Methuen, a leading English press. Indeed, the mere fact that Carson identifies him as “British” associates him with a country that had been instrumental in the rise of modern science and was notable for many important scientists and scientific facilities.
Her “appeal to authority” here is typical of similar appeals throughout her book. In the next several pages, for instance, she mentions “the ecologist Paul Shepard” and the “entomologist Neely Turner,” and throughout her work Carson cites the work of numerous other writers, just as in her Acknowledgments she lists the names of numerous scientists who helped her by sharing their expertise.
Meanwhile, in paragraph 28 (which begins with the words “The important of plants”), Carson cites various statistics to further strengthen her case, as in the following sentence:
The United States Office of Plant Introduction alone has introduced almost 200,000 species and varieties of plants from all over the world. Nearly half of the 180 or so major insect enemies of plants in the United States are accidental imports from abroad, and most of them have come as hitchhikers on plants.
Note that Carson is careful here to identify her source of information: presumably it is from the United States Office of Plant Introduction itself that she has derived these statistics. In any case, the use of the statistics is quite effective. It is hard to imagine that a single government bureaucracy could be responsible to introducing 200,000 new forms of life into the United States, and so the statistic is both eye-catching and memorable. So, too, is the statistic that follows. Rather than using statistics in a way that seems dull and tedious, Carson uses them to catch and hold our attention. She does not overwhelm us with numbers, but the numbers she does use seem genuinely important and striking.