  Many scientists have expressed concerns about potential catastrophic risks
associated with new technologies. But expressing concern is one thing,
identifying serious candidates another. Such risks are likely to be novel,
rare, and difficult to study; data will be scarce, making speculation
necessary. Scientists who raise such concerns may face disapproval not only as
doomsayers, but also for their unconventional views. Yet the costs of false
negatives in these cases -- of wrongly dismissing warnings about catastrophic
risks -- are by definition very high. For these reasons, aspects of the
methodology and culture of science, such as its attitude to epistemic risk and
to unconventional views, are relevant to the challenges of managing extreme
technological risks. In this piece I discuss these issues with reference to a
real-world example that shares many of the same features, that of so-called
'cold fusion'.
