summary the answer to the question posed in the title is offered at three levels. at times the differences are due to the limitations of the equipment employed, deficiencies in the samples used, or bias in the interpretation of the data. at other times, the key factor is the paradigm on which the research is based. finally, disagreements can be caused by worldview differences; in such cases the cause is not scientific but philosophical in nature and can be attributed to the different presuppositions of the researchers. the essay contrasts the biblical-christian worldview, as understood by seventh-day adventists, and secular humanism, exploring their implications.