The study of causal judgment is dominated by two lines of research. According to one of these, what makes something a cause is that the effect's occurrence depends on the cause. Some of these theories hold that a cause increases the probability of the effect; others hold that a cause is necessary for the effect. In the second line of research, what makes something a cause is that it has a physical connection to the effect. Some of these theories hold that a cause must transmit force or energy to the effect. These two lines of research make commitments to different mental representations of causal relationships. In the present studies, participants were asked to make causal judgments about stories where the two kinds of theories make conflicting predictions. The results can be explained by neither kind of theory alone, although a hybrid model may be able to explain the results.