 J. Megill (2007) has raised a problem for epiphenomenalism based on the assumption that properties must be individuated by their causal relations. Since epiphenomenalists deny efficacy to phenomenal qualities, the only causal relations to which they could appeal to individuate them would be causes of events with those qualities. However, different causes may produce the same effect. Thus, appeal to difference of causes alone is an insufficient basis for individuation of phenomenal qualities.