Johnson has been accused of being intellectually dishonest in his arguments advancing intelligent design and attacking the scientific community. Johnson has employed numerous equivocations regarding the term "naturalism," failing to distinguish between methodological naturalism (in which science is used to study the natural world and says nothing about the supernatural) versus philosophical naturalism (the philosophical belief that nothing exists but the natural world, and adopts as a premise the idea that there is no supernatural world or deities). In fact-checking Johnson's books "Darwin on Trial" and "Defeating Darwinism by Opening Minds", Brian Spitzer, an associate professor of biology at the University of Redlands, argued that almost every scientific source Johnson cited had been misused or distorted, from simple misinterpretations and innuendos to outright fabrications. Spitzer described "Darwin on Trial" as the most deceptive book he had ever read.