Although uniformitarianism is widely recognized as the basic principle of geology, the geological literature is riddled with false and misleading statements as to what uniformitarianism means. These misconceptions must be eliminated so geologists feel free to propose any scientifically reasonable hypotheses and because they open geology to unwarranted attack from outside science. The twelve specific fallacies identified herein are that uniformitarianism (1) is unique to geology; (2) was originated by Hutton; (3) was named by Lyell, who established its current meaning; (4) should be called “actualism” because it refers to “real” causes; (5) holds that only currently acting processes operated during geologic time; (6) holds that the rates of processes have been constant; (7) holds that only gradual processes have acted and that catastrophes have not occurred during Earth's past; (8) holds that conditions on Earth haven't changed much; (9) holds that Earth is very old; (10) is a testable theory; (11) is limited in both time and place; and (12) holds that the laws governing nature have been constant through time. Geologists should abandon the terms “uniformitarianism” and “actualism” because they are fruitless, confusing, and inextricably associated with many fallacious concepts. Instead, the fundamental philosophical approach of science should be recognized as basic to geology.