This chapter shows that the quantitative and qualitative cultures differ on the issue of symmetry. Whereas quantitative research tends to analyze relationships that are symmetric, qualitative research focuses on relationships that have asymmetric qualities. Causal models and explanations can be asymmetric in a variety of ways. This chapter deals mainly (though not exclusively) on the so-called “static causal asymmetry,” in which the explanation of occurrence is not the mirror image of that of nonoccurrence. After comparing symmetric and asymmetric models, the chapter looks at examples of asymmetric explanations using set-theoretic causal models. It highlights the difficulty of translating the fundamental symmetry of standard statistical models into the basic asymmetry of set-theoretic models, as well as the difficulty of capturing the asymmetry of set-theoretic models with the standard symmetric tools of statistics.