 It is fair to say that coherence theorists have yet to reach anything like consensus on how best to define coherence in probabilistic terms. Nevertheless, the debate so far has given rise to a much more fine-grained understanding of what the options are and what consequences they have. What is more, some quite surprising conclusions can be drawn even with this issue largely unresolved: all we need to assume in order to prove that no coherence measure can be truth conducive, in a sense to be explained, is that those measures respect the Content Determination Thesis.