Reductionism is a necessary part of any attempt to make sense of the world. We have to compartmentalize the objects of our analysis and description, thereby reducing some set of terms or phenomena to others. While this form of analytic reduction is necessary for both humanism and science, ontological reduction is different. Ontological reductionists postulate that there is a single level of description that can explain all the rest, whether it is the psychological level or the physical. While most cognitive scientists of religion recognize the difference between descriptive and ontological reduction, many nevertheless insist that the individualistic cognitive terms they work with, and that they see as in the head, are the real things that explain human behaviour and language, including religion. They construct orderly individualistic concepts for cognition and then devise experiments in the laboratory and in the wild to test those concepts.