Nonreductive physicalism provides an appealing solution to the nature of mental properties. But its success as a theory of mental properties has been called into doubt by claims that it cannot adequately handle the problems of mental causation, as it leads either to epiphenomenalism or to thoroughgoing overdetermination. I argue that these apparent problems for the nonreductivist are based in fundamental confusion about causation and explanation. I distinguish two different types of explanation and two different relations to which they appeal: causation and determination. I argue that these types of explanation do not compete with one another, nor do these relations jointly result in overdetermination. In closing I develop a nonreductivist solution to mental causation which avoids both the hazards of epiphenomenalism and of overdetermination and so demonstrates a way to save nonreductive physicalism from the problems of mental causation.