Making decisions based on risks is not easy, but commonplace. The
problem with COVID-19 is that so many risks are unknown, as probability
distributions are wanting. Moreover, decisions based on fundamental
uncertainty tend to be speculative and potentially
harmful.6 Decisions based on ambiguity βare not just
potentially misleading β they are a fundamental contradiction in
terms.β8 Therefore it is crucial to clarify
definitions. Additionally, ignorance poses great challenges, as we do
not know what we do not know β and hence where to search for solutions.