  Public debates driven by incomplete scientific data where nobody can claim
absolute certainty, due to current state of scientific knowledge, are studied.
The cases of evolution theory, global warming and H1N1 pandemic influenza are
investigated. The first two are of controversial impact while the third is more
neutral and resolved. To adopt a cautious balanced attitude based on clear but
inconclusive data appears to be a lose-out strategy. In contrast overstating
arguments with wrong claims which cannot be scientifically refuted appear to be
necessary but not sufficient to eventually win a public debate. The underlying
key mechanism of these puzzling and unfortunate conclusions are identified
using the Galam sequential probabilistic model of opinion dynamics. It reveals
that the existence of inflexible agents and their respective proportions are
the instrumental parameters to determine the faith of incomplete scientific
data public debates. Acting on one's own inflexible proportion modifies the
topology of the flow diagram, which in turn can make irrelevant initial
supports. On the contrary focusing on open-minded agents may be useless given
some topologies. When the evidence is not as strong as claimed, the inflexibles
rather than the data are found to drive the opinion of the population. The
results shed a new but disturbing light on designing adequate strategies to win
a public debate.
