A recurring theme in Engelmann's work refers to professional manipulators engaging others in activity for its own sake regardless of its nature or consequences. In his last paper, "Science under Siege", he warned of two sorts of religion edging their way into science. The first is the supernaturalist view, the sort of view held by Creationists. The second is more subtle. It is the naturalist view. Advocates of either notion urge us to believe things that cannot be put to the test. Whether God created the heavens and the earth in six days or whether there are parallel universes have nothing whatsoever to do with science no matter how gladly true believers would have it so. Central to all science is the testable hypothesis. If it is not there, we are not talking about science.