According to a popular model of mental causation, an irreducible mental cause M1 brings about an irreducible mental effect M2 by bringing about M2's supervenience base (ground, realizer, etc.), P2. Call this ‘the Downward Causation View’. This paper raises doubts about the Downward Causation View on grounds that M1 does not cause M2 immediately and there is no causal chain from M1 to M2. Prima facie, then, M1 does not cause M2 on this view. But a theory of mental causation ought to account for how some mental phenomena cause other mental phenomena; so rival theories are to be preferred. After setting out the problem, I consider replies; all fail.