This article disputes the common view that social science explanations depend on discovery of lawlike generalizations from which descriptions of social outcomes can be derived. It distinguishes between governing and phenomenal regularities, and argues that social regularities are phenomenal rather than governing. In place of nomological deductive arguments, the article maintains that social explanations depend on the discovery of causal mechanisms underlying various social processes. The metaphysical correlate of this argument is that there are no social kinds: types of social entities that share a common casual constitution giving rise to strong regularities of behavior. The article turns next to a consideration of the character of social causation and argues for a microfoundational interpretation of social causation: social causal powers are embodied in the constraints and opportunities that institutions present to individual agents. Finally, it is noted that these arguments have consequences for the credibility of social predictions: it is argued that predictions in social science are generally unreliable.