E.J. Lowe has recently proposed a model of mental causation on which mental events are emergent, thus exerting a novel, downward causal influence on physical events. Yet on Lowe's model, mental causation is at the same time empirically undetectable, and in this sense is "invisible". Lowe's model is ingenious, but I don't think emergentists should welcome it, for it seems to me that a primary virtue of emergentism is its bold empirical prediction about the long-term results of human physiology. Here I'll try to restore emergentism's empirical status, but my broader aim is to use Lowe's model to explore some central topics in the mental causation debate, including the "causal closure" of the physical world and the nature of causal powers.