stylistic:tone, quality:corruption
Content

Biographer Mark Hamilton Lytle writes that Carson "quite self-consciously decided to write a book calling into question the paradigm of scientific progress that defined post-war American culture." The overriding theme of Silent Spring is the powerful—and often adverse—effect humans have on the natural world.

Carson's main argument is that pesticides have detrimental effects on the environment; they are more properly termed biocides, she argues, because their effects are rarely limited to the target pests. DDT is a prime example, but other synthetic pesticides come under scrutiny, many of which are subject to bioaccumulation. Carson also accuses the chemical industry of intentionally spreading disinformation and public officials of accepting industry claims uncritically. Most of the book is devoted to pesticides' effects on natural ecosystems. However, four chapters also detail cases of human pesticide poisoning, cancer, and other illnesses attributed to pesticides. Regarding DDT and cancer, the subject of so much subsequent debate, Carson only briefly mentions the topic:

In laboratory tests on animal subjects, DDT has produced suspicious liver tumors. Scientists of the Food and Drug Administration who reported the discovery of these tumors were uncertain how to classify them but felt there was some "justification for considering them low grade hepatic cell carcinomas." Dr. Hueper now gives DDT the definite rating of a "chemical carcinogen."

Carson predicted increased consequences in the future, especially as targeted pests develop pesticide resistance. At the same time, weakened ecosystems fall prey to unanticipated invasive species. The book closes with a call for a biotic approach to pest control as an alternative to chemical pesticides.

Regarding DDT, Carson never called for an outright ban. Part of the argument she made in Silent Spring was that even if DDT and other insecticides had no environmental side effects, their indiscriminate overuse was counter-productive because it would create insect resistance, making them useless in eliminating the target insect populations:

No responsible person contends that insect-borne disease should be ignored. The question that has now urgently presented itself is whether it is either wise or responsible to attack the problem by methods that are rapidly making it worse. The world has heard much of the triumphant war against disease by controlling insect vectors of infection. However, it has heard little of the other side of the story—the defeats, the short-lived triumphs that now strongly support the alarming view that the insect enemy has been made actually stronger by our efforts. Even worse, we may have destroyed our very means of fighting.

Carson further noted that "Malaria programmes are threatened by resistance among mosquitoes" and emphasized the advice given by the director of Holland's Plant Protection Service: "Practical advice should be 'Spray as little as you possibly can' rather than 'Spray to the limit of your capacity'... Pressure on the pest population should always be as slight as possible."